Absorbent article having rapid acquiring, multiple layer absorbent core

ABSTRACT

An absorbent article, such as a disposable diaper, adult incontinent pad, sanitary napkin, and the like, is disclosed which has a rapid acquiring, multiple layer absorbent core. The absorbent article may be in an improved shape that can be worn in the wearer&#39;s usual undergarments. The absorbent article of the present invention comprises a liquid pervious topsheet, a liquid impervious backsheet, and a multiple layer absorbent core positioned between the topsheet and the backsheet. The multiple layer absorbent core comprises at least one rapid acquiring acquisition/distribution layer and at least one storage layer positioned subjacent each acquisition layer. The acquisition/distribution layers have a fluid acquisition/distribution rate of at least about 2 cubic centimeters of synthetic urine per second when tested under a pressure of about 28 grams per square centimeter. The storage layers at least partially comprise a &#34;high-speed&#34; absorbent gelling material which is capable of reaching at least about 40% of its absorptive capacity in less than or equal to about 10 seconds. A multiple layer absorbent core for an absorbent article is also disclosed.

This is a division of application Ser. No. 07/931,122, filed on Aug. 17,1992, now U.S. Pat. No. 5,304,161 which was a continuation ofapplication Ser. No. 07/637,090, filed on Jan. 3, 1991 now abandoned.

FIELD OF THE INVENTION

This invention relates to absorbent articles, such as disposablediapers, incontinent articles, sanitary napkins and the like, havingmultiple layer absorbent cores. This invention also relates to a rapidacquiring, multiple layer absorbent core for an absorbent article and toan absorbent article, such as an adult incontinent pad, which whenprovided with such an absorbent core, may be in an improved shape thatcan be worn in the wearer's usual undergarments.

BACKGROUND OF THE INVENTION

Absorbent articles such as disposable diapers, adult incontinent pads,sanitary napkins and the like come in many different sizes and shapes.Diapers and incontinent pads are generally garments worn by infants orincontinent persons that are drawn up between the legs and fastenedabout the waist of the wearer. Sanitary napkins are designed to receiveand contain vaginal discharges, such as menses, and are typically heldadjacent to the human body through the agency of a garment, such as anundergarment or a panty, or a specially designed belt.

There is a continual effort to make such absorbent articles morecomfortable and discrete and less obtrusive for the wearer. This isparticularly true in the case of adult incontinent pads. Adultincontinent pads, by their nature, have previously been made fairlythick so they can handle the relatively large quantities of bodyexudates, such as urine, they receive. The desire for less bulkyincontinent pads is particularly great among incontinent persons, manyof whom are elderly adults, because it can be embarrassing to weardiaper-like articles. In addition, most individuals would rather usesome type of article that could be worn with the undergarments theynormally wear.

One key component of an absorbent article that contributes to its sizeand bulk is the absorbent body used therein. Typically, absorbentarticles comprise a liquid pervious material that faces the wearer'sbody, a liquid impervious material that faces the wearer's clothing, andan absorbent body or absorbent core that is sandwiched between theliquid pervious material and the liquid impervious material. In priorabsorbent articles, a material comprising comminuted wood pulp, referredto as airfelt, was used in the absorbent core to serve the functions ofacquiring, distributing, and storing liquids and other exudatesdeposited on the surface of the absorbent article. One of thedisadvantages of using airfelt was that a thick layer of airfelt had tobe used to obtain the needed capacity.

Recent attempts to improve the effectiveness of absorbent cores haveincluded distributing particles of absorbent gelling material throughoutor in portions of the absorbent core. Some of these improvements aredescribed in U.S. Pat. No. 4,610,678 issued to Paul T. Weisman andStephen A. Goldman on Sep. 9, 1986; U.S. Pat. No. 4,673,402 issued toPaul T. Weisman, Dawn I. Houghton, and Dale A. Gellert on Jun. 16, 1987;and European Patent Application EP-A-254,476 assigned to The Procter &Gamble Company, published Jan. 27, 1988, the disclosures of which areincorporated by reference herein. Another improvement to theeffectiveness of absorbent cores is described in U.S. Pat. No. 4,781,711issued on Nov. 1, 1988 to Dawn I. Houghton and Nicholas A. Ahr, thedisclosure of which is also incorporated by reference herein. While theabsorbent articles described in the above references work quite well,the search for improved absorbent articles that are capable of rapidlyand efficiently absorbing increasingly greater quantities of exudateshas continued.

The structure of the absorbent core ideally should be such that theabsorbent article absorbs exudates immediately when they are dischargedso that such exudates will not pool or otherwise remain on top of thecore. The absorbent core ideally should also be constructed so exudatesinitially absorbed will be immediately transported to a place within theabsorbent core where they can be stored. One problem with many of theprior absorbent articles that used absorbent gelling materials is thatthe absorbent gelling materials do not absorb liquid exudates as fast asthey are deposited on the core. Slow absorbing absorbent gellingmaterials, thus, do little to increase the immediately availablecapacity of the core. Such absorbent gelling materials typically requireseveral seconds or minutes to absorb fluids.

The absorbent core should also provide a system of distribution andstorage for exudates that efficiently uses the entire capacity of theabsorbent core. One problem that often arises in absorbent articleswithout such a system (particularly those absorbent articles that usethe same layer or batt of material to serve the different functions ofacquiring, distributing, and storing exudates) is that the storagecapacity of the absorbent article is exhausted prematurely. This canoccur in several different ways. In many absorbent articles, thesaturation of the absorbent material in the region where exudates areinitially deposited reduces the ability of the absorbent material totransport additional exudates to other parts of the core. Thisphenomenon can also lead to the undesirable pooling of exudates on topof the core discussed above.

In other absorbent articles the effectiveness of absorbent corescontaining particles of absorbent gelling material can be adverselyaffected by a phenomenon called "gel blocking". The term "gel blocking"describes a situation that occurs when a particle of absorbent gellingmaterial is wetted and the surface of the particle swells so as toinhibit liquid transmission into the interior of the absorbent core.Wetting of the interior of the absorbent core, therefore, takes placevia a very slow diffusion process. In practical terms, this means thatacquisition of liquid by the absorbent core is much slower than thedischarge of the liquids to be absorbed, and leakage from the absorbentarticle may take place well before the particles of absorbent gellingmaterial in the absorbent core are fully saturated or before the liquidcan diffuse or wick past the "blocking" particles into the rest of theabsorbent core.

Therefore, a need exists for an absorbent article of an improved shapethat has an absorbent core that quickly acquires and distributesexudates throughout the absorbent core where they can be stored.

It is an object of the present invention to provide an absorbentarticle, particularly an incontinent article, of an improved shape thatcan be worn in the wearer's usual undergarments.

It is another object of the present invention to provide an absorbentcore for an absorbent article which is especially efficient inacquiring, distributing, and storing exudates as they are deposited onthe absorbent article.

In particular, it is an object of the present invention to provide anabsorbent core that has a system in which the functions of acquiring anddistributing exudates are handled by layers that are separate from thelayers used for storing exudates. Ideally, such a system will allowexudates to be continuously acquired and distributed to storage layersby layers that are not subject to the prior problems of saturation andgel blocking.

These and other objects of the present invention will be more readilyapparent when considered in reference to the following description andwhen taken in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION

The present invention provides absorbent articles, such as disposablediapers, incontinent pads, sanitary napkins and the like that havemultiple layer absorbent cores that are capable of acquiring andcontaining liquids in an especially effective and efficient manner. Inone embodiment, the absorbent articles of the present invention can bein an elongated-pear shape that can be worn in the wearer'sundergarments.

The absorbent articles of the present invention comprise a liquidpervious topsheet, a liquid impervious backsheet joined with thetopsheet, and an absorbent core positioned between the topsheet and thebacksheet. The absorbent core of the present invention comprisesmultiple layers. The multiple layers comprise at least one pair oflayers. In each pair of layers, the uppermost layer is a rapid acquiringexudate acquisition/distribution layer (typically a low density web orbatt of material). A storage layer comprised at least partially of ahigh-speed absorbent gelling material positioned subjacent eachacquisition/distribution layer.

The acquisition/distribution layers have a fluidacquisition/distribution rate of at least about 2 cubic centimeters ofsynthetic urine per second when the acquisition/distribution layer istested according to the Fluid Acquisition/Distribution Test under apressure of about 28 grams per square centimeter. Theacquisition/distribution layers in at least some embodiments willcomprise a "low density" web or batt of material, such as a nonwovenweb, with a density of less than or equal to about 0.1 grams per cubiccentimeter and a basis weight of from about 17 to about 270 grams persquare meter, when the acquisition/distribution layers are placed undera load of 0.1 psi (7 grams per square centimeter).

The storage layers are comprised at least partially of a "high-speed"absorbent gelling material. A "high-speed" absorbent gelling material isan absorbent gelling material which reaches at least about 40% of itsabsorptive capacity in less than or equal to about 10 seconds.Preferably, this will be a material that has a total capacity of atleast about 25 times its dry weight in fluid, such as synthetic urine,and a liquid acquisition rate of greater than or equal to about 0.8grams of synthetic urine per second per gram of such material.Preferably, the storage layers each have a basis weight of between about20 to about 1,200 grams/square meter and a density of less than or equalto about 0.2 grams per cubic centimeter.

In use, it is believed that the exudate acquisition/distribution layeris capable of quickly taking exudates into itself as they are depositedon the absorbent article and distributing such exudates to the lowerstorage layer in a manner that substantially reduces or eliminates priorproblems of saturation of the materials adjacent the zone of exudateapplication and gel blocking. It is believed that the combination of thelayers of the particular materials used provides a structure that isalso capable of quickly storing the absorbed liquids.

While not wishing to be bound by any particular theory, it is believedthat the multiple layer absorbent core distributes exudates by acascading effect. It is believed that the manner of acquisition,distribution, and storage of the multiple layer absorbent core can beanalogized to the filling of an ice cube tray with water in that whenone region of the absorbent core is filled, exudates will quickly flowlaterally to the sides of the filled region to begin filling otherunfilled regions.

The present invention also relates to multiple layer absorbent coresthat can be employed in absorbent articles of other sizes and shapes.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter which is regarded as formingthe present invention, it is believed that the invention will be betterunderstood from the following description which is taken in conjunctionwith the accompanying drawings in which like designations are used todesignate substantially identical elements, and in which:

FIG. 1 is a plan view of a preferred embodiment of the absorbent articleof the present invention.

FIG. 2 is an enlarged transverse sectional view of the absorbent articleof the present invention taken along line 2--2 of FIG. 1.

FIG. 3 is a longitudinal sectional view of the absorbent article of thepresent invention taken along line 3--3 of FIG. 1.

FIG. 4 is a plan view of an absorbent article having an aperture of adifferent configuration.

FIG. 5 is a plan view of an absorbent article having a multiplicity ofapertures.

FIG. 6 is a transverse sectional view taken from an angle similar tothat of FIG. 2 of an embodiment of the absorbent article of the presentinvention which has an alternative core arrangement.

FIG. 7 is a transverse sectional view similar to that of FIG. 6 of anembodiment of the absorbent article of the present invention which hasanother alternative core arrangement.

FIG. 8 is a perspective view of an incontinent brief that includes theabsorbent core of the present invention.

FIG. 9 is a transverse sectional view of the incontinent brief shown inFIG. 7, taken along line 8--8 of FIG. 7.

FIG. 10 is a schematic view of the apparatus used in the HorizontalFluid Acquisition/Distribution Rate Test.

DETAILED DESCRIPTION OF THE INVENTION 1. Overall Characteristics of theAbsorbent Article

The overall characteristics of the absorbent article of the presentinvention will be discussed first.

FIGS. 1-3 show a preferred embodiment of a disposable absorbent articleof the present invention. The absorbent article of the present inventionshown in the drawings is of an improved shape that can fit into thewearer's undergarments. The absorbent article has a multiple layerabsorbent core that is capable of quickly acquiring, distributing, andstoring body exudates.

As used herein, the term "absorbent article" refers to articles whichabsorb and contain body exudates. More specifically, the term refers toarticles which are placed against or in proximity to the body of thewearer to absorb and contain the various exudates discharged from thebody. The term "absorbent article" is intended to include diapers,incontinent articles, sanitary napkins, and the like. The term"incontinent articles" is intended to include pads, undergarments (padsheld in place by a suspension system of some type, such as a belt, orthe like), inserts for absorbent articles, capacity boosters forabsorbent articles, briefs, bed pads, and the like, regardless ofwhether they be worn by adults or other incontinent persons. The term"disposable" refers to articles which are intended to be discarded aftera single use. That is, disposable articles are not intended to belaundered or otherwise restored or reused.

In the preferred embodiment illustrated, the absorbent article is anadult incontinent pad (or "pad") designated 20. (It should be understoodthat even though the preferred embodiment is illustrated and describedin the form of an incontinent pad, the description of the variouscomponent parts of the incontinent pad 20 will also apply generally toother types and shapes of absorbent articles that are made according tothe present invention.)

The incontinent pad 20 has two surfaces, a body-contacting surface or"body surface" 20a and a garment surface 20b. The incontinent pad 20 isshown in FIG. 1 as viewed from its body surface 20a. The body surface20a is intended to be worn adjacent to the body of the wearer. Thegarment surface 20b of the incontinent pad 20 (shown in FIG. 2) is onthe opposite side and is intended to be placed adjacent to the wearer'sundergarments when the incontinent pad 20 is worn.

The incontinent pad 20 has two centerlines, a longitudinal centerline land a transverse centerline t. As used herein the term "longitudinal"refers to a line, axis or direction in the plane of the incontinent pad20 that is generally aligned with (e.g., approximately parallel to) avertical plane that bisects a standing wearer into left and right bodyhalves when the incontinent pad 20 is worn. The term "transverse" refersto the line, axis or direction generally perpendicular to thelongitudinal direction which lies within the plane of the incontinentpad 20. The incontinent pad 20 has a longitudinal dimension that runs inthe general direction of the longitudinal centerline l, and a transversedimension that runs in the general direction of the transversecenterline t. The incontinent pad 20 is typically longer in thelongitudinal dimension than in the transverse dimension.

FIG. 1 shows that the incontinent pad 20 has two spaced apartlongitudinal edges 22 and two spaced apart transverse or end edges (or"ends") 24, which together form the periphery 26 of the incontinent pad20. When the incontinent pad 20 is worn, one of the end edges 24 will beoriented toward the front of the wearer, and one of the end edges 24will be oriented toward the rear of the wearer. The end edge 24 orientedtoward the front of the wearer, the "front end edge", is designated 24a,and the end edge oriented toward the rear of the wearer, the "rear endedge" or "back end edge", is designated 24b.

The shape of the absorbent article 20 of the present invention in planview is shown in FIG. 1. While the absorbent article 20 may have anyshape known in the art, the preferred embodiment of the absorbentarticle, incontinent pad 20, shown in FIG. 1 is symmetrical about itslongitudinal centerline l, but is asymmetrical about its transversecenterline t. The absorbent article 20 can be divided into three regionsin plan view: a first end region 28, a central region 30, and a secondend region 32.

The first end region 28 is intended to be to the front of the wearer'sbody when the incontinent pad 20 is worn. The second end region 32 isintended to be to the wearer's rear when the incontinent pad 20 is worn.The central region 30 lies between the first and second end regions, andis intended to be worn in the area of the wearer's crotch. The first endregion 28 and the second end region 32 extend outwardly from the centralregion 30 toward the ends 24a and 24b respectively, a distance of about1/8 to about 1/3 of the total length of the incontinent pad 20; althoughthe exact size of the first and second end regions will vary accordingto the precise design and intended positioning of the incontinent pad20.

The shape of the longitudinal edges 22 of the incontinent pad 20 in thefirst end region 28 is defined by curved convex outward (or outwardlyarcuate with relation to each other) lines on each side of thelongitudinal centerline l. The lines that form the longitudinal edges 22change direction of curvature and curve inward toward each other in atleast a portion of the central region 30. The longitudinal side edges 22are generally straight and parallel to each other in the second endregion 32 in the embodiment shown in FIGS. 1-3. In alternativeembodiments, the longitudinal side edges 22 could be inwardly taperedtoward the longitudinal centerline l in the second end region 32 so thatthe longitudinal side edges 22 become closer together near the rear endedge 24b of the incontinent pad 20 than they are adjacent the centralregion 30. The end edges 24 of the incontinent pad 20 are rounded andcurved convex outwardly.

The overall shape of the incontinent pad 20 shown in FIG. 1 could bedescribed in a number of ways. The incontinent pad 20 could be said tobe dog bone-shaped or hourglass-shaped on one side of the transversecenterline t, and could be said to have longitudinal side edges on theother side of the transverse centerline t that are either approximatelyparallel to each other or inwardly tapered. Alternatively, theincontinent pad 20 could be viewed as being of an elongated pear-shape.

There are several reasons for providing an incontinent pad in such ashape. The first end region 28 of the incontinent pad 20 is worn to thewearer's front. This is the area in which the wearer's genitals arelocated, and thus, where urine is typically deposited. The first endregion 28 of the incontinent pad 20 has been made larger than the otherregions of the pad to provide a large target to receive this urine. Thecentral region 30 is made narrower than the first end region 28 so theincontinent pad 20 will fit comfortably between the wearer's legs andwill accommodate the wearer's movements. The second end region 32 isnarrower than the widest portion of the first end region 28 so thatthere will be less tendency for the second end region 32 to buckle andwedge in the crevice of the user's body between the buttocks.

The dimensions of the preferred incontinent pad 20 shown in FIG. 1 areas follows. The incontinent pad 20 has an overall length l₁ of about 35centimeters (cm.). The overall width of the pad 20 w₁ at its widestportion (in the first end region 28, not including the span of theoptional side flaps 60 described below) is about 16 cm. The overalllength l₂ of the absorbent core 43 of the incontinent pad 20 is about 33cm. The overall width w₂ of the absorbent core 42 at its widest portionis about 14 cm. The width of the absorbent core 42 narrows to about 9cm. in the central region 30 at the transverse centerline t, and toabout 8.5 cm. in the second end region 32. The latter dimension ismeasured inboard, i.e., toward the intersection of the longitudinal andtransverse centerlines l and t, of the place where the curvature of theend edge 24b of the incontinent pad 20 begins. In addition, as shown inFIG. 1, the topsheet 34 and the backsheet 36 extend outward away fromthe intersection of the longitudinal and transverse centerlines l and tto form a border 44 approximately 1 cm. wide around the circumference ofthe absorbent core 42. The incontinent pad 20 has a surface area ofapproximately 55 square inches (about 355 cm²), and is much smaller thantraditional diaper-like incontinent briefs.

It should be understood, however, that the above dimensions arepreferred for the particular embodiment of the incontinent pad 20 shownin FIGS. 1-3. The multiple layer absorbent core 42 of the presentinvention can be used in other types of absorbent articles and can be inmany other shapes and sizes depending on the type of absorbent articleand the absorbent capacity needed.

FIG. 2 shows the individual components of the incontinent pad 20. Theincontinent pad 20 of the present invention generally comprises threeprimary components. These include a liquid pervious topsheet 34, aliquid impervious backsheet 36, and a multiple layer absorbent core 42.The absorbent core 42 is positioned between the topsheet 34 and thebacksheet 36. There are two basic types of layers in the absorbent core42, acquisition/distribution layers 46, comprised of a low density (or"high loft") material capable of rapidly taking in and distributingexudates, and storage layers 48 comprised at least partially of ahigh-speed absorbent gelling material.

The layers of the absorbent core 42 are arranged in pairs so that anacquisition/distribution layer 46 is always on top of a storage layer 48(that is, the acquisition/distribution layer 46 in issue is alwayspositioned between the topsheet 34 and the underlying storage layer 48).In the embodiment shown in FIGS. 1-3, the absorbent core 42 comprisesfour layers. As shown in FIG. 2, the four layers comprise from the topof the absorbent core 42 to the bottom: a first acquisition/distributionlayer 46', a first storage layer 48', a second acquisition/distributionlayer 46", and a second storage layer 48".

The incontinent pad 20 of the present invention can also be providedwith any optional additional components that are known in the art. Theoptional components may include one or more longitudinal barrier shields56 (shown in FIG. 1), one or more transverse barrier shields 58 (alsoshown in FIG. 1), side flaps or "wings" 60 (FIGS. 1 and 2), an adhesivefastening means 62 (FIG. 2), and a removable cover strip or releaseliner 64 (FIG. 2). In the embodiment shown in FIG. 2, the incontinentpad 20 of the present invention is provided with one longitudinalbarrier shield 56 along each longitudinal edge 22 of the pad, and onetransverse barrier shield 58 along each end edge 24 of the pad. The sideflaps or "wings" 60 may be at least partially folded around the crotchportion of the wearer's undergarments. The adhesive fastening means 62serves as a means for attaching the incontinent pad 20 to the wearer'sundergarments. The removable release liner 64 covers the adhesivefastening means 62 in order to keep the adhesive from becomingcontaminated or sticking to a surface other than the crotch portion ofthe undergarment prior to use.

In the following sections of this description, the characteristics ofthe individual components are discussed in greater detail in Section 2.The optional components of the incontinent pad 20 are discussed inSection 3. The alternative embodiments of the absorbent article arediscussed in Section 4. The test methods used herein are described inSection 5.

2. The Individual Components of the Absorbent Article

Looking at the components of the incontinent pad 20 more specifically,FIG. 2 shows the liquid pervious topsheet (or simply the "topsheet") 34overlies the other components of the incontinent pad 20 (other than thebarrier shields). The topsheet 34 is oriented towards and contacts thebody of the wearer. The topsheet 34 is the portion of the incontinentpad 20 that initially receives bodily discharges. The topsheet 34 has abody-facing side (or "body surface") 34a and a core-facing side 34b. Thebody-facing side 34a of the topsheet 34 generally forms at least aportion of the body-contacting surface ("body surface") 20a of theincontinent pad 20.

The topsheet 34 should permit liquids to readily transfer through itsthickness toward the absorbent core 42. The topsheet 34 should,therefore, be liquid pervious. The topsheet 34 should also be flexibleand nonirritating to the wearer's skin. As used herein the term"flexible" refers to materials which are compliant and readily conformto the shape of the body or respond by easily deforming in the presenceof external forces. Preferably the topsheet 34 is not noisy, to providediscretion for the wearer. The topsheet 34 should be clean in appearanceand somewhat opaque to hide the bodily discharges collected in andabsorbed by the absorbent components. The topsheet 34 should furtherexhibit good strikethrough and a reduced tendency to rewet, permittingbodily discharges to rapidly penetrate the topsheet 34 and make theirway to the the absorbent core 42, but not allowing such discharges toflow back through the topsheet 34 to the skin of the wearer.

A suitable topsheet 34 may be made from a number of different materials,such as porous foams, reticulated foams, apertured plastic films,natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g.,polyester or polypropylene fibers), or from a combination of natural orsynthetic fibers. Preferably, the topsheet is made of a hydrophobicmaterial to isolate the wearer's skin from liquids in the absorbent core42.

There are a number of manufacturing techniques which may be used tomanufacture the topsheet 34. For example, the topsheet 34 may be woven,nonwoven (e.g., spunbonded, carded or the like), foamed, or cast. Apreferred topsheet 34 is spunbonded and thermally bonded by meanswell-known to those skilled in the fabric art. Preferably, the topsheethas a weight from about 18 to about 30 grams per square meter, a minimumdry tensile strength of at least about 400 grams per centimeter in themachine direction and a wet tensile strength of at least about 55 gramsper centimeter in the cross-machine direction.

The backsheet 36 is shown in FIG. 2. The backsheet 36 is the componentof the incontinent pad 20 that prevents the exudates from wettingarticles which contact the incontinent pad 20. Typically, the articleswhich come in contact with the incontinent pad 20 would be the wearer'sundergarments. The present invention is also concerned, however, withkeeping the wearer's body and clothing free from soiling.

The backsheet 36 has a core-facing side 36a and a garment side 36b. Atleast a portion of the core-facing side 36a of the backsheet 36 willordinarily face the core 42. It is also within the scope of the presentinvention for portions of the core-facing side 36a of the backsheet 36(such as wings 60) to be folded so that they may not necessarily alwaysface the core 42. However, the core-facing side 36a of the backsheet 36can be distinguished from the garment side 36b of the backsheet 36because the core-facing side 36a is the side of the backsheet 36 that isjoined to the topsheet 34 and adjacent to the core 42. The garment side36b of the backsheet 36 generally forms the garment surface 20b of theincontinent pad 20.

The backsheet 36 may be any flexible, liquid impervious material thatprevents discharges collected by the incontinent pad 20, (particularlydischarges which may not be completely absorbed by the core 36), fromescaping the incontinent pad 20 and soiling the undergarments andclothing of the wearer. Preferably, the backsheet 36 is not noisy, toprovide discretion for the wearer. The backsheet 36 may also beimpervious to malodorous gases generated by bodily discharges, so thatthe malodors do not escape and become noticed by the wearer and others.In other alternatives, the backsheet 36 may be pervious to water vapor(but not to liquids) so that any such vapors trapped between theincontinent pad 20 and the wearer's skin can escape to make the productmore comfortable to wear.

Preferably, at least a portion of the backsheet 36 is manufactured froma thin plastic film, although other suitable liquid impervious materialsmay also be used. In one preferred embodiment, the backsheet 36 is apolyethylene film having a thickness of from about 0.012 mm (0.5 mil) toabout 0.051 cm (2.0 mils), although other flexible, liquid imperviousmaterials may be used. A suitable polyethylene film is manufactured byMonsanto Chemical Corporation and marketed in the trade as Film No.8020. The backsheet 36 is may also be embossed and/or matte finished toprovide a more cloth-like appearance.

In a most preferred embodiment, the backsheet 36 is comprised of twolayers. In the embodiment shown in FIG. 2, the backsheet 36 comprises afirst layer 38 of lofted material disposed on the garment side 36b ofthe backsheet 36. The purpose of the first layer 38 is to provide acomfortable, nonirritating surface against the body of the wearer. Thefirst layer 38 may be comprised of any suitable material, such as anonwoven material. Preferably, the first layer 38 comprises ahydrophobic nonwoven material. The second layer 40 may be disposed onthe core-facing side 36a of the backsheet 36, and may comprise a fluidimpervious film. A low density polyethylene material about 0.01 to about0.05 millimeters in thickness, preferably about 0.02 millimeters inthickness, has been found to work well as this second layer 40. Apolyethylene film, such as is sold by the Ethyl Corporation, VisqueenDivision, under model XP-39385 is particularly well suited for thissecond layer 40. The backsheet 36 may also be made of a soft, cloth-likematerial which is hydrophobic relative to the topsheet 34. A polyesteror polyolefinic fiber backsheet 36 has been found to work well. Aparticularly preferred soft, cloth-like backsheet 36 material is alaminate of a polyester nonwoven material and a film such as describedin U.S. Pat. No. 4,476,180 issued to Wnuk on Oct. 9, 1984, thedisclosure of which patent is hereby incorporated by reference herein.

The topsheet 34 and the backsheet 36 are joined together in any suitablemanner. As used herein, the term "joined" encompasses configurationswhereby the topsheet 34 is directly secured to the backsheet 36 byaffixing the topsheet 34 directly to the backsheet 36, andconfigurations whereby the topsheet 34 is indirectly secured to thebacksheet 36 by affixing the topsheet 34 to intermediate members whichin turn are affixed to the backsheet 36. In a preferred embodiment, thetopsheet 34 and the backsheet 36 are joined directly to each other inthe periphery of the incontinent pad 20 by attachment means (not shown)such as an adhesive or any other attachment means as are known in theart. For example, a uniform continuous layer of adhesive, a patternedlayer of adhesive, or an array of separate lines or spots of adhesivemay be used to join the topsheet 34 to the backsheet 36.

The characteristics of the multiple layer absorbent core 42 are alsoshown in FIG. 2. The multiple layer absorbent core (or simply the"absorbent core", or "the core") 42 serves as a means of absorbingbodily fluids. In particular, the absorbent core 42 is the means forcollecting and containing bodily discharges, such as urine, which aredeposited on the core 42 or which otherwise traverse through the liquidpermeable topsheet 34. The absorbent core 42 has a body-facing side 42aand a garment-facing side 42b.

The core 42 need not have a total absorbent capacity much greater thanthe total amount of bodily discharges to be absorbed. In the embodimentshown in FIG. 2, the core 42 is preferably made as narrow and thin aspossible, so it is comfortable for the wearer. For the embodimentdescribed herein (that is, a core used in pads designed for persons withmoderate to heavy incontinence) the capacity of the core should bebetween about 100 to about 600 grams of synthetic urine (synthetic urineis described in Section 5 below which is entitled "Test Methods"). Thecore 42 can be sized and provided with different capacities to fit theuse intended for the absorbent article. Thus, the core 42 may be madesmaller and may have a lower absorbent capacity when it is used inincontinent pads that are intended for people with light incontinence,and when used in other types of absorbent articles, such as in diapersand sanitary napkins.

The core 42 should also be conformable and nonirritating to the wearer'sskin. The core 42 should be sized to register with the topsheet 34 andbacksheet 36. The core 42 is preferably positioned between the topsheet34 and backsheet 36. The position of the core 42 prevents the absorbentmaterial of the core 42 from shredding or becoming detached while theincontinent pad 20 is worn. The position of the core 42 also ensuresproper containment of bodily discharges. The core 42 may be of any shapesuch as in the same general shape as the incontinent pad 20 describedabove, or in any other suitable shape in other embodiments. Forinstance, the core 42 may be rectangular or hourglass-shaped.

The absorbent core 42 preferably comprises two or more distinct layers.The preferred embodiment of the multiple layer absorbent core 42 shownin FIG. 2 comprises four layers. In the embodiment shown in FIG. 2, thefour layers comprise from the top of the absorbent core 42 to thebottom: a first acquisition/distribution layer 46', a first storagelayer 48', a second acquisition/distribution layer 46", and a secondstorage layer 48". There can be any number of pairs ofacquisition/distribution layers 46 and storage layers 48 in the multiplelayer absorbent core 42, from one pair of layers to a virtually infinitenumber of a plurality or multiplicity of pairs of layers.

There are two general requirements for the arrangement of the layers ofthe core 42. One requirement is that the materials be stacked so astorage layer 48 is positioned beneath an acquisition/distribution layer46 so that the absorbed exudates will have some place to be stored. Theother requirement is that when there is more than one pair ofacquisition/distribution and storage layers, there must be some paththrough which exudates can flow to the underlying layers when thestorage layers that lie above such layers become full. In the embodimentshown in FIG. 2, this flow path is provided by an aperture 52 in thefirst storage layer 48'.

It should be understood that for the purpose of this invention, thelayers described herein refer merely to zones of the absorbent core andare not necessarily limited to single layers or sheets of material.Thus, the exudate acquisition/distribution layers 46 and the storagelayers 48 may actually comprise strips of material, loose or bondedparticles or fibers, laminates of material, or other combinations ofsuch materials, such as several sheets or webs of the types of materialdescribed below. Thus, as used herein, the term "layer" also includesthe terms "layers" and "layered".

The exudate acquisition/distribution layers 46 will be discussed first.The exudate acquisition/distribution layers (or simply"acquisition/distribution layers") 46 are positioned on top of thestorage layers 48. The term "acquisition", as used herein refers to theability to take in (that is, acquire into itself) exudates, particularlyliquid exudates. The acquisition/distribution layers 46 may take inexudates by a number of means. The acquisition/distribution layers 46may simply provide void space for the exudates to enter, or they maytake in exudates by means such as absorption, or capillary action. Theterm "distribution", as used herein refers to the ability to transportexudates, particularly liquid exudates, to other areas of the absorbentarticle.

The exudate acquisition/distribution layers 46 serve several functions.The acquisition/distribution layers 46 should absorb exudates depositedon the absorbent article 20 (or received from the layers located above)as quickly as possible to reduce or eliminate pooling or accumulation ofthese exudates on top of the core 42. Preferably, theacquisition/distribution layers 46 are capable of taking in exudates atthe same rate or at a rate which is faster than exudates are depositedonto the surface of the core 42. The acquisition/distribution layers 46should also be able to transport exudates taken in to locations withinthe core 42 where they can be stored. Preferably, this transportationand storage is at the same or faster rate that exudates are deposited onthe core 42 so that exudates will not "back up" and pool on top of thecore 42 for lack of a mechanism to immediately store the same.

In addition, in the preferred embodiments of the present invention, theacquisition/distribution layers 46 and the storage layers 48 shouldfunction independently. In such embodiments, the functions of acquiringand distributing exudates may be handled nearly entirely by theacquisition/distribution layers 46, and the storage layers 48 may not berequired to transport exudates to other parts of the core 42. Thestorage layers 48 can, as a result, be designed without taking intoaccount any exudate distribution considerations which reduced theeffectiveness of many prior disposable absorbent articles.

The acquisition/distribution layers 46 should also preferably be able tocontinue to function when the wearer's activities cause compressiveforces to be placed on the absorbent article. Theacquisition/distribution layers 46 should preferably maintain sufficientvoid space (or "void volume") when subjected to such forces and alsowhen wetted so that they will be able to continue to transport liquidexudates. If this is the case, the acquisition/distribution layers willhave capacity to not only handle initial gushes of liquid exudates, butwill also be able to handle subsequent gushes. To maintain such voidspace, the acquisition/distribution layers 46 should be both dryresilient and wet resilient, and should also be moisture insensitive.The term "moisture insensitive", as used herein, refers to materialsthat will not collapse when wetted or otherwise be affected by thepresence of moisture. A good discussion of the terms contained in thisparagraph is contained in U.S. patent application Ser. No. 07/198,032filed May 24, 1988 in the name of George S. Reising, et al., thedisclosure of which is incorporated by reference herein.

The acquisition/distribution layers 46 are comprised of a low density(or "high loft") web or batt of material. The terms "low density" and"high loft", as used herein, refer to a batt of material having adensity of less than or equal to about 0.1 grams per cubic centimeter.

The acquisition/distribution layers 46 can be comprised of a number ofdifferent types of materials. The acquisition/distribution layers 46 canbe nonwoven webs of fibers, foams, or any other suitable material thatprovides the desired rapid fluid acquisition and distributionproperties. If the acquisition/distribution layers 46 are webs offibrous nonwoven material, they can be comprised at least partially ofnatural fibers (such as wood, e.g., in the form of airfelt, or cottonfibers), at least partially of synthetic fibers (such as rayon fibers,polyester, polyethylene, polyethylenetheraphalate (also known as "PET"),or polypropylene fibers), cross-linked cellulose fibers, foams, or anyequivalent material or combination of materials. Suitable cross-linkedcellulose fibers are described in U.S. Pat. No. 4,888,093, issued Dec.19, 1989 to Cook, et al.; U.S. Pat. No. 4,822,543, issued Apr. 18, 1989to Dean, et al.; U.S. Pat. No. 4,889,595, issued Dec. 26, 1989 toSchoggen, et al.; U.S. Pat. No. 4,889,596, issued Dec. 26, 1989 toSchoggen, et al.; U.S. Pat. No. 4,898,642, issued Feb. 6, 1990 to Moore,et al.; and U.S. Pat. No. 4,935,022, issued Jun. 19, 1990 to Lash, etal., the disclosures of which are incorporated by reference herein.

If the acquisition/distribution layers 46 are fibrous nonwoven webs ofmaterial, they can be comprised of fibers of any length. Preferably,however, the fibers used in the acquisition/distribution layers 46 arestaple fibers. The terms "staple fibers", or "staple length fibers", asused herein, refer to fibers that are between about 0.125 inches andabout 3.0 inches (about 3 millimeters and about 7.5 centimeters) inlength.

The acquisition/distribution layers 46 can also contain absorbentgelling materials (also known as "hydrogels", "superabsorbent polymericmaterials", or "supersorbers") provided that such materials are notpresent in such amounts or distributed in such a manner that theyinterfere with the desired acquisition and distribution characteristicsof the acquisition/distribution layers 46. Absorbent gelling materialsare described in greater detail in a number of references, includingU.S. Pat. No. 4,781,711, issued to Dawn I. Houghton and Nicholas A. Ahron Nov. 1, 1988, the disclosure of which is incorporated by referenceherein. If the acquisition/distribution layers 46 contain absorbentgelling materials, the specific type of absorbent gelling materials usedin the acquisition/distribution layers 46 can be different from thetype(s) of absorbent gelling materials used in other parts of theabsorbent core 42. Alternatively, the acquisition/distribution layers 46can be substantially free of absorbent gelling materials.

Preferably, the acquisition/distribution layers 46 are comprised of atleast some synthetic fibers (e.g., at least 10% by weight) so theacquisition/distribution layers 46 will be resilient enough to transportexudates throughout the core 42 when the absorbent article 20 issubjected to compressive forces when it is worn. Although natural fibersand absorbent gelling materials will provide theacquisition/distribution layers 46 with absorptive capacity and theability to wick exudates, these characteristics are not absolutelyrequired in the acquisition/distribution layers 46 of the presentinvention. Preferably, the acquisition/distribution layers 46 arecomprised of nonwoven webs of synthetic fibers such as polyester,polyethylene, polyethylenetheraphalate, and polypropylene fibers, andare substantially free of absorbent gelling materials. In one preferredembodiment, the acquisition/distribution layers 46 are nonwoven webscomprised of about 80% 15 denier per fiber polyester fibers, and about20% binder fibers. (Denier is a unit of fineness for a fiber. A "denier"represents the fineness of a fiber weighing one gram for each 9,000meters.)

There are a number of manufacturing techniques which may be used tomanufacture the acquisition/distribution layers 46. For example, theacquisition/distribution layers 46 may be woven or nonwoven, e.g., airlaid, spunbonded, carded or the like. A preferred material for theacquisition/distribution layers 46 is a carded and thermally bonded, lowdensity nonwoven material. The fibers in the acquisition/distributionlayers 46 may be bonded with a binder material such as acrylic latexrather than thermally bonded, or the fibers may be unbonded. Inespecially preferred embodiments, the fibers in theacquisition/distribution layers 46 are unbonded. In any event, thematerial comprising the acquisition/distribution layers 46 should bearranged in an open structure to provide the desired void space.

Preferably, the acquisition/distribution layers 46 have a basis weightfrom about 0.5 to about 8 ounces per square yard (about 17 to about 270grams per square meter), and a density from about 0.02 to about 0.10grams per cubic centimeter (g/cc). The density of theacquisition/distribution layers 46 (and the storage layers 48, and anyother layers for which densities are given) is calculated from the basisweight of the layer and its caliper. All measurements are made on newlyunpacked, unfolded, and dissected absorbent articles. Unless otherwisestated, the densities and calipers are measured with a sample under aload of 0.1 psi (7 grams per square centimeter). The basis weight ismeasured by die-cutting a certain size sample and weighing the sample ona standard scale. The weight and area of the sample determine the basisweight of the sample. The caliper is measured using a standard gauge.The density and basis weight values of the acquisition/distributionlayers 46 do not include the weight of any absorbent gelling materialscontained in the layers. The density and basis weight values given belowof the storage layers 48, however, include the weight of the absorbentgelling materials contained therein.

It should be understood that the characteristics (for example, thematerial composition, basis weight, and density) of theacquisition/distribution layers 46 may differ between layers when thereare more than one acquisition/distribution layer 46.

For instance, in the case of the preferred embodiment shown in FIGS.1-3, when there are two acquisition/distribution layers 46, the topacquisition/distribution layer, first acquisition/distribution layer46', has a lower basis weight than the bottom acquisition/distributionlayer, second acquisition/distribution layer 46". In the preferredembodiment shown in FIGS. 1-3, the first acquisition/distribution layer46' has a basis weight that is preferably between about 0.5 and about 4ounces per square yard (about 17 to about 135 grams per square meter),most preferably about 2 ounces per square yard (about 70 grams persquare meter), and a density from about 0.03 to about 0.05 grams percubic centimeter (g/cc). In this preferred embodiment, the loweracquisition/distribution layer, second acquisition/distribution layer46", has a basis weight that is preferably between about 4 to about 8ounces per square yard (about 70 to about 270 grams per square meter),most preferably about 6 ounces per square yard (about 200 grams persquare meter), and a density from about 0.03 to about 0.05 grams percubic centimeter (g/cc). As will be described in greater detail below,the corresponding storage layers 48 also preferably have upper layerswith lower basis weights than those of the lower layers.

It is believed that such an arrangement (making the top layers thinner)will be more comfortable for the wearer. This is particularly true whenthe uppermost storage layer, such as first storage layer 48', has alarge aperture 52 for allowing fluids to pass to the underlying layers.If the uppermost storage layer 48' has a large aperture, the wearer maynotice the difference in thickness between the apertured portion of theuppermost storage layer and the unapertured portion of the uppermoststorage layer. For this reason, it is desirable to make the uppermoststorage layer relatively thin so the difference in thickness between theapertured and unapertured portions will be less noticeable. Theuppermost acquisition/distribution layer 46' that forms the first pairof layers with the first storage layer 48', is also made relatively thinso that its size corresponds with the size of the first storage layer48'.

The ability of the acquisition/distribution layers 46 to acquire anddistribute exudates is referred to herein as the "horizontal fluidacquisition/distribution rate". The horizontal fluidacquisition/distribution rate may also be referred to by any abbreviatedform of its name. The term "horizontal fluid acquisition rate", as usedherein, refers to the rate at which the acquisition/distribution layers46 allow fluid applied from a point source to enter and flow throughitself while the layer is under a preselected pressure. The horizontalfluid acquisition rate is measured by the Horizontal FluidAcquisition/Distribution Test described in Section 5. The term "pointsource" as used herein refers to the type of source of fluid that isdescribed in Section 5. The point source is not, however, limited tosingle drops of fluid or the like.

The desired horizontal fluid acquisition rate of theacquisition/distribution layers 46 varies depending on the intended useof the absorbent article because the amount of fluids the absorbentarticle is required to handle will vary with the intended use of theabsorbent article. The incontinent pad 20 illustrated in FIGS. 1-3 isintended for use by adults suffering from moderate to severe bladderincontinence. In this case, the horizontal fluid acquisition rate of theacquisition/distribution layers 46 should be at least about 8.0 cubiccentimeters of synthetic urine/second (cc/sec) when theacquisition/distribution layer 46 being tested is under a pressure ofabout 0.4 pounds/square inch (psi.) (a pressure of about 28 grams persquare centimeter). Preferably, the horizontal fluid acquisition rate ofthe acquisition/distribution layers 46 is at least about 12 cc/sec.under a pressure of about 0.4 psi (28 g/cm²). In alternative uses,however, the horizontal fluid acquisition/distribution rate can be aslow as about 2 cc/sec. of synthetic urine under a pressure of aboutabout 28 g/cm². A horizontal fluid acquisition/distribution rate ofabout 2 cc/sec. would, for example, be suitable for use in a sanitarynapkin, and a horizontal fluid acquisition/distribution rate of about 4cc/sec. would be suitable for use in a disposable diaper. Theacquisition/distribution layers 46 should, preferably, maintain thedesired horizontal fluid acquisition/distribution rates after they havebeen wetted with exudates.

Preferably, the acquisition/distribution layers 46 are sufficiently wetresilient that they have a transverse post-compression recovery when wetof at least about 80% following compression of up to 25% of their width.To determine the transverse post-compression recovery, a sample of theacquisition/distribution layer material of a determined width isimmersed in synthetic urine until substantially saturated. The saturatedsample is placed on a platen or base plate between vise-like jaws. Thejaws are brought together to reduce the width of the sample by about 75%and are held in the narrowing position for 30 seconds. The jaws are thenreleased and the sample is allowed to recover for 30 seconds and thedegree of recovery of the initial width is measured. The recovered widthexpressed as a percentage of the initial width is the transversepost-compression recovery.

The other type of layers that comprise the absorbent core 42 are thestorage layers 48. The storage layers 48 serve to store exudates thathave been transported to them for storage by theacquisition/distribution layer that lies above (and by theacquisition/distribution layer that lies below, if such a layer ispresent) each storage layer 48.

The storage layers 48 need not be especially effective for distributingexudates to other parts of the core 42. This requirement is preferablyfulfilled by the acquisition/distribution layers 46. (The storage layers48, should, however, allow exudates to move around within the storagelayers themselves to the extent necessary to properly utilize thecapacity of the storage layer.) The storage layers 48 can, therefore, bedesigned and constructed without being unduly burdened by considerationsof exudate distribution. Such considerations would normally limit thestorage capacity of the core by limiting the concentration andabsorption speed of the absorbent gelling materials contained in theabsorbent core.

Preferably, the storage layers 48 are capable of storing exudates asquickly as they are transported to the storage layers 48, or morequickly. The absorbent core 42 is preferably of such a construction thatexudates will always have a place within the core 42 where they can bequickly stored until the capacity of the absorbent core 42 is reached.Such absorbent cores should not be subject to the prior problems, suchas that of gel blocking, that caused the cores of many prior absorbentarticles to be prematurely exhausted before their full capacity wasused.

The storage layers 48 of the present invention are comprised at leastpartially of high-speed absorbent gelling materials. (That is, thestorage layers 48 can be comprised partially of high-speed absorbentgelling materials, or entirely of such materials.) The term "absorbentgelling materials" as used herein generally refers to water-insoluble,water-swellable polymeric substances that are capable of absorbing waterin an amount which is at least 10 times the weight of the substance inits dry form.

The term "high-speed" absorbent gelling materials as used herein, meansthose absorbent gelling materials that are capable of absorbing exudatesat such a rate that they reach at least about 40%, preferably at leastabout 50%, and most preferably at least about 90% of their capacity inless than or equal to about 10 seconds. The percent rate of capacity canbe measured using the "Tea Bag" Test described in Section 5.

Another way to express the rate at which absorbent gelling materialsabsorb fluids is by specifying the rate at which fluids are absorbed perweight of the absorbent gelling material (for example, the rate ofabsorption in grams per second per gram of absorbent gelling material).Expressed in this alternative manner, the preferred high-speed absorbentgelling materials referred to herein are those absorbent gellingmaterials that have a total capacity of at least about 25 times theirweight in fluids, and are capable of absorbing fluids at the rate of atleast about 0.8 grams/second per gram of absorbent gelling material(corresponds to the rate of about 40% capacity specified above), morepreferably about 1.25 grams/second per gram of absorbent gellingmaterial (corresponds to the rate of about 50% capacity), still morepreferably 1.5 grams/second per gram of absorbent gelling material, andmost preferably about 2.25 grams/second per gram of absorbent gellingmaterial (corresponds to the rate of about 90% capacity). (Allreferences herein to the number of times its weight that the absorbentgelling materials can absorb refers to multiples of the weight of theabsorbent gelling materials in their dry form.)

Suitable high-speed absorbent gelling materials are currently availablein a number of different forms. One type of absorbent gelling materialsis in particulate form. The term "particulate", as used herein can referto particles in any form, such as in the form of pellets or flakes. Anexample of particulate absorbent gelling materials (though notnecessarily high-speed particulate absorbent gelling materials) arethose made in accordance with U.S. Pat. No. 4,654,039 issued Mar. 31,1987 to Brandt, et al. the disclosure of which is incorporated byreference herein. Several types of absorbent gelling materials arediscussed in U.S. Pat. No. 4,781,711 to Houghton, et al., previouslyincorporated by reference herein. The preferred form of absorbentgelling materials for use in the present invention, however, is afibrous high speed absorbent gelling material.

The term "fibrous absorbent gelling materials" as used herein, meansthose absorbent gelling materials that are in the form of fibers. Suchfibers (though not necessarily high-speed fibrous absorbent gellingmaterials) are discussed more fully in U.S. Pat. No. 4,855,179, issuedAug. 8, 1989, to Bourland, et al., the disclosure of which isincorporated by reference herein. The term "fibrous absorbent gellingmaterials", as used herein, is intended to include absorbent gellingmaterials in the form of fibers that are comprised entirely of absorbentgelling material and bi-component fibers that are comprised at leastpartially of other materials which have their surfaces coated withabsorbent gelling materials.

Fibrous absorbent gelling materials are preferred for several reasons.Fibrous absorbent gelling materials can be easily incorporated into thestructure of a nonwoven material. Fibrous absorbent gelling materialsremain in place better than absorbent gelling materials in some otherforms when compressive forces and other forces act on the absorbentarticle. Further, fibrous absorbent gelling materials are generallysofter and more flexible than particulate absorbent gelling materials.Fibrous absorbent gelling materials also may have less tendency to causeholes in the backsheet 36 when they are in their dry state than someparticulate absorbent gelling materials. Fibrous absorbent gellingmaterials can be distributed within a layer of material so that thefibers are generally spaced away from adjacent fibers a sufficientdistance. As a result of this last characteristic, fibrous absorbentgelling materials will have a reduced tendency to come in contact witheach other and cause gel blocking when they absorb liquids and swell.

A suitable fibrous high speed absorbent gelling material is known asFIBERSORB SA7000 and is available from Arco Chemical Company of NewtonSquare, Pa. FIBERSORB SA7000 is capable of absorbing fluid at the rateof at least about 1.9 grams per second per gram of such a material. Anespecially preferred fibrous high-speed absorbent gelling material isknown as FIBERSORB SA7200, and is also made by Arco Chemical Company,but is not commercially available. FIBERSORB SA7200 is capable ofabsorbing fluid at the rate of at least about 2 grams per second pergram of such material.

It is desirable to use high speed absorbent gelling materials because,due to their high speed, they can substantially contribute to theimmediately available capacity of the absorbent core 42. The absorbentgelling materials typically used in prior absorbent articles requiredseveral seconds or minutes to reach a substantial level of absorptivecapacity. They were, therefore, of little value during the initialapplication of exudates to the absorbent articles. They became ofsignificant value primarily during subsequent application of exudates.

It may be desirable to mix other materials with the high-speed absorbentgelling materials in the storage layers 48. There may be severalpurposes for including such other materials in the storage layers 48.Other materials may be used to hold the particles or fibers of theabsorbent gelling material in place. They may also be used to bind theabsorbent gelling material, or other components of the storage layers 48together. They may be used to maintain space between the individualparticles or fibers of absorbent gelling material in order to insurethat adequate space is available for the absorbent gelling material toswell to its full size when it reaches its absorptive capacity.

The other materials that may be included in the storage layers 48 may beany of the types of materials specified above for use in theacquisition/distribution layers 46, and possibly a binder of some type.

However, as described in greater detail below, the characteristics (suchas material composition, density, basis weight, and horizontal fluidacquisition rate) of the storage layers 48 do not have to be the same asthe acquisition/distribution layers 46. The relative proportions of thetypes of the materials, in particular the amount of synthetic fibersthat may be used, however, should be less than is used in theacquisition/distribution layers 46 because it is desirable to havegreater absorptive capacity in the storage layers 48. The specificamounts of materials used are described below.

Binders, such as binder fibers, are used to bind the fibers thatcomprise the storage layers 48 to each other and to bind such fibers tothe high-speed absorbent gelling materials used in the storage layers48. A suitable binder fiber, if one is used, should be capable ofbonding to the types of fibers described herein as being suitable foruse in the storage layers 48 at temperatures that are less than themelting temperature of such fibers. A preferred commercially availablebinder fiber is known as KODEL 410 and is manufactured by the EastmanChemical Products, Inc. of Kingsport, Tenn.

The composition of the materials used to form the storage layers 48 canvary within certain limits. All percentages of material compositionreferred to in this description are by weight, unless otherwisespecified. The percentage of each of the materials used must be suchthat the total of the percentages equals 100%. In addition, allpercentages of composition (and horizontal fluidacquisition/distribution) specified in this description and the appendedclaims are meant to include absorbent articles that have the specifiedpercentage measured in some portion of the layer in issue (e.g., in atleast some section of the absorbent article), regardless of whether theentire layer has the percentage in issue.

The storage layers 48 can contain between about 10% or 20% to about 100%high speed absorbent gelling materials; as much as about 80% naturalfibers, such as wood pulp; as much as about 80% synthetic fibers, suchas polyester fibers; as much as about 80% cross-linked cellulose fibers;and as much as about 20% binder fibers. When the storage layers 48 aredescribed as having "as much as" a specified percentage of a material,this means that the material may be used in the layer, but it does nothave to be present in the layer. In other words, the layer could havenone of the material (0%), or it could have the material present in anamount between some small percentage such as 0.1% and the specifiedpercentage of the material (e.g., 30%). One particularly preferredstorage layer 48 is a thermally bonded mixture that contains about 50%FIBERSORB SA7000 absorbent gelling material, about 30% wood pulp, andabout 20% KODEL 410 binder fiber.

There are a number of manufacturing techniques that may be used tomanufacture the storage layers 48. For example, the storage layers 48can be air laid, or carded. A preferred storage layer 48 is an air laidmixture of high speed absorbent gelling materials and airfelt.Typically, an air laying process involves mixing the components in air,and condensing and rearranging the mixture on a forming screen. Anysuitable conventional air laying process may be used.

The storage layers 48 should have a basis weight of from about 0.01 toabout 0.8 grams per square inch (from about 20 to about 1200 grams persquare meter), and a density of less than about 3 grams per cubic inch(about 0.183 grams per cubic centimeter (g/cc)). As in the case of theacquisition/distribution layers 46, the characteristics (for example,the material composition, basis weight, and density) of the storagelayers 48 may differ between layers when there is more than one storagelayer 48.

Preferably, in the case of the preferred embodiment shown in FIGS. 1-3,where there are two storage layers, the top storage layer, first storagelayer 48' has a basis weight from about 0.01 to about 0.4 grams persquare inch (about 20 to about 600 grams per square meter), mostpreferably about 0.2 grams per square inch (about 300 grams per squaremeter), and a density of less than about 2 grams per cubic inch (about0.12 g/cc), most preferably about 1.5 grams per cubic inch (about 0.092g/cc). The lower storage layer, second storage layer 48", has a basisweight from about 0.2 to about 0.8 grams per square inch (about 300 toabout 1200 grams per square meter), most preferably about 0.4 grams persquare inch (about 600 grams per square meter), and a density of lessthan about 2 grams per cubic inch (about 0.12 g/cc), most preferablyabout 1.5 grams per cubic inch (about 0.092 g/cc).

The different layers of the multiple layer absorbent core 42 may bebonded together by any suitable means such as spray gluing, or they maybe unbonded.

When there is more than one pair of the layers described above (that is,when there is more than one acquisition/distribution layer and more thanone storage layer), there should be some type of interconnection betweeneach pair of layers because exudates will generally not be able totravel through a full storage layer (such as first storage layer 48'shown in FIG. 2) to underlying acquisition/distribution layers andstorage layers because of the reduction in void space therein andswelling of the absorbent gelling materials. A completely full storagelayer will tend to block the flow of exudates. Thus, the pairs oflayers, particularly the acquisition/distribution layers 46 in eachpair, should be in fluid communication with each other. The term "fluidcommunication" simply means that fluids should be able to pass betweenthe layers or pairs of layers. This fluid communication between thelayers may be provided by any suitable means. For instance, in theembodiment shown in FIGS. 1-3, there is at least one fluid passageway orpath (or simply "passageway") 50 for exudates to travel through from theone layer, such as first acquisition/distribution layer 46', to theunderlying layers, such as second acquisition/distribution layer 46".

The terms "passageway" or "path", as used herein, refer to a structurethrough which exudates may flow from one layer to another layer. Thepassageway 50 may be any suitable structure that will allow exudates toflow from an upper acquisition/distribution layer to a loweracquisition/distribution layer or storage layer. The term "passageway"is thus not limited to a structure of any particular shape. Forinstance, a suitable passageway could comprise one or more apertures,one or more pieces of fluid pervious material that connect two layers,or it could comprise portions of the layers themselves, or anarrangement of layers that interconnect or simply touch each other. Inaddition, or as an alternative to the above, the passageway couldcomprise a low density area, or any of the other types of structuresdescribed in U.S. patent application Ser. No. 07/198,032 filed May 24,1988 in the name of George S. Reising, et al., the disclosure of whichwas previously incorporated by reference herein and in U.S. Pat. No.4,880,419 issued Nov. 14, 1989 to Irving S. Ness, the disclosure ofwhich is hereby also incorporated by reference herein.

If the passageway 50 comprises one or more apertures 52, there areseveral factors that should be considered. The apertures 52 should beproperly positioned, and should be sufficient in size to transferexudates from one layer to another. The apertures 52 should be locatedat places where exudates would otherwise accumulate when the upperstorage layer or layers reach capacity. Typically, this place will beimmediately below the region where exudates are deposited onto theincontinent pad 20 (referred to as the "area or zone of typical exudatedeposition"). The apertures 52 in each storage layer 48 should,therefore, be located between the transverse centerline t and the frontend edge 24a (that is, in the front half of the incontinent pad 20). Thewidth of the apertures 52 should be such that the apertures 52 do notclose up if the incontinent pad 20 is compressed in the transversedirection when worn, or when the absorbent gelling materials swell whenwetted. The incontinent pad 20 may have any number of apertures 52, fromone to virtually an infinite number of a plurality or multiplicity ofapertures.

The area that the apertures 52 should be located in preferably, at aminimum, covers at least the area shown in dotted lines in FIG. 4. Thisarea is in the shape of an isosceles triangle. The base of the isoscelestriangle is generally perpendicular to the longitudinal centerline l,and is spaced about 2 inches (about 5 cm.) from the front end edge 24aof the incontinent pad 20. The length of the base of thetriangular-shaped area is about 2 inches (about 5 cm.). The height isabout 3 inches (about 7.6 cm.). The triangular-shaped area covers about3 square inches (about 19 square centimeters).

A particularly preferred passageway 50 is shown in FIGS. 1-3. Thepassageway 50 shown in FIGS. 1-3 comprises a single aperture 52 in thefirst storage layer 48'. It is believed that when there is only oneaperture 52 in the storage layer or layers 48, the dimensions of such asingle aperture 52 need to be made relatively large to avoid thetendency of the aperture 52 to close up when the incontinent pad 20 isworn and shut off the flow of exudates to the lower layers. The aperture52 extends the entire length of the first storage layer 48' in theembodiment shown in FIGS. 1-3. In the embodiment shown in FIGS. 1-3, thewidth of the aperture 52 is greater in the first end region 28 than inparts of the central region 30 and in the second end region 32 of theincontinent pad 20. Preferably, the width of the aperture 52 is at leastabout 2 inches (about 5 cm.) in the first end region 28. The preferredaperture 52 shown in FIGS. 1-3 has longitudinal side walls that followthe curvature of the longitudinal side edges 22 of the incontinent pad20.

The storage layer 48' and the aperture 52 in the embodiment shown inFIGS. 1-3 can be thought of in an alternative manner since the aperture52 is relatively wide and extends the full length of the core 42. Thestorage layer 48' can be thought of as being in the form of at least twostrips of material, such as strips 48a' and 48b', instead of being inthe form of a layer with an aperture. If the first storage layer 48' isthought of in this manner, in the preferred embodiment shown in FIGS.1-3, the strips 48a' and 48b' that form the first storage layer 48' arepreferably each between about 0.75 to about 1.5 inches (about 2 to about4 cm.) wide.

FIG. 4 shows an alternative embodiment of the incontinent pad 20 of thepresent invention that has a single aperture 52 located in the area oftypical liquid deposition, between the transverse centerline t and thefront end edge 24a of the incontinent pad 20. As shown in FIG. 4, theedge of the aperture 52 closest to the front end edge 24a of theincontinent pad 20 may be spaced inward toward the transverse centerlinet a distance of about 1 inch (about 2.54 cm.) since exudates are notusually deposited within the 1 inch region between the edge of theaperture 52 and the front end 24a of the pad 20.

FIG. 5 shows an alternative embodiment of the incontinent pad 20 of thepresent invention that has a multiplicity of apertures 52. When thereare a multiplicity of apertures 52 in the storage layer(s) 48, the sizeof each aperture 52 can be smaller than when there is only a singleaperture 52. There will be less tendency for all of such apertures 52 toclose up simultaneously. The apertures 52 should not be made so small,however, that absorbent gelling materials which have absorbed exudatesand swelled block the openings that the apertures 52 provide.Preferably, each aperture 52 will have a width of at least about 1/4inch (about 0.65 cm.), although smaller widths are possible. Theaperture or apertures 52 that connect the layers may be circular asshown in FIG. 5, or any other suitable shape, including square,rectangular, oval, and irregularly-shaped.

3. Optional Components of the Absorbent Article

The incontinent pad 20 of the present invention may be provided withoptional additional components.

The incontinent pad 20 of the present invention may be provided withbarrier shields along the edges of the pad. The incontinent pad 20 shownin FIG. 1 is provided with longitudinal barrier shields 56 along eachlongitudinal edge 22 of the pad and transverse barrier shields 58 alongeach transverse, or end edge 24 of the pad.

The longitudinal barrier shields 56 are used primarily for two purposes,although they may also serve other functions.

The longitudinal barrier shields 56 first serve to prevent thoseexudates that are in the process of being transported by theacquisition/distribution layers 46 from flowing out of the incontinentpad 20 along the longitudinal edges 22 of the same. As described above,the materials chosen for the acquisition/distribution layers 46 aretypically very efficient at transporting liquid exudates in directionsin the plane of the pad. This is particularly true when theacquisition/distribution layers 46 are made entirely of synthetic fiberssince such fibers will not absorb fluids. In such embodiments, fluidswill be transported so rapidly that they will literally flow out thesides of the core 42 if they are not restrained from doing so. Thelongitudinal barrier shields 56 prevent this from occurring.

Importantly, this first function of the longitudinal barrier shields 56differs from the function of conventional barrier leg cuffs and thelike. Conventional barrier leg cuffs serve primarily to contain exudateswhich have pooled on the surface of either the topsheet or absorbentcore of the absorbent article from leaking out of the absorbent article.Thus, it is necessary that such conventional barrier leg cuffs form a"stand up" barrier to the flow of exudates. Ideally, there should be nopooling on top of the absorbent core of the present invention, so thelongitudinal barrier shields 56 may lie flat on top of the topsheet 34.Alternatively, they may be positioned between the core 42 and thetopsheet 34 and may lie flat on top of the core 42.

The second function of the longitudinal barrier shields 56 is to directexudates toward portions of the core 42 that have capacity available toabsorb exudates. Liquid exudates that are deposited on the core 42 willtend to be distributed by the acquisition/distribution layers 46radially outward from the place where they were deposited. Since thecore 42 of the incontinent pad 20 is made relatively narrow incomparison to its length, liquid exudates will reach the longitudinaledges 42c of the core 42 much sooner than they will reach the ends 42dof the absorbent core 42. The longitudinal barrier shields 56 directexudates toward the ends 42d of the core 42, particularly toward theback end 42d' of the core 42. Since the back end edge 24b of the pad 20is typically lower than the front end edge 24a when the incontinent pad20 is worn, liquids will tend to flow by gravity towards the back endedge 24b along the longitudinal barrier shields 56.

The incontinent pad 20 may also be provided with one or more transversebarrier shields 58 along the end edges 24 of the pad. In the embodimentshown in FIG. 1, the incontinent pad 20 has a transverse barrier shield58 along each end edge 24 of the pad. In alternative embodiments,however, the incontinent pad 20 of the present invention may only haveone transverse barrier shield 58. In such a case, the transverse barriershield 58 should preferably be positioned at the rear end edge 24b ofthe incontinent pad 20 because exudates will be more likely to leak outof the rear end edge 24b of the pad, rather than out of the front endedge 24a since (as described above) the front end edge 24a is likely tobe more elevated when worn. Liquid exudates will generally not tend toflow out of the front end edge 24a of the pad 20 unless there are somewicking fibers in the core at this end of the pad.

The barrier shields may be manufactured from a wide variety of materialssuch as polyethylene, polypropylene, polyester, rayon, nylon, foams,plastic films, formed films, and elastic foams. A number ofmanufacturing techniques may be used to manufacture the barrier shieldsfrom these materials. For example, the barrier shields may be woven,nonwoven (e.g., spunbonded, carded, or the like). One particularlypreferred barrier shield comprises a two layer laminate comprising alayer of nonwoven material and a polyethylene film. In other alternativeembodiments, the barrier shields may comprise a material, such as a lowtack or no tack hot melt material, that is printed on the incontinentpad 20. Such an alternative type of barrier shield may be printed by anysuitable process, including by gravure printing or flexographic printingprocesses.

If desired, the incontinent pad 20 may be additionally provided withflaps 60 that extend outwardly from each longitudinal edge 22 of theincontinent pad 20. The flaps 60 may be in any suitable configuration.Suitable flaps 60 may, for example, be made in accordance with theteachings of U.S. Pat. Nos. 4,589,876, issued May 20, 1986 to VanTilburg and 4,687,478, issued Aug. 18, 1987 to Van Tilburg, thedisclosures of which patents are incorporated herein by reference.

In addition, as shown in FIG. 2, the garment side 36b of the backsheet36 may include a means for attaching the incontinent pad 20 to theundergarment of the wearer ("attaching means") 62. Preferred attachingmeans 62 may include mechanical fasteners or, more preferably, adhesivefastening means, such as a pressure sensitive adhesive. The pressuresensitive adhesive may be applied to the garment side 36b of thebacksheet 36 in a number of different configurations.

Such configurations include, but are not limited to a single strip ofadhesive 62 along the longitudinal centerline l of the incontinent pad20 (shown in FIG. 1), two parallel strips of adhesive, two symmetricallyopposite, convex outwardly oriented strips of adhesive, a generallycentered rectangular patch of adhesive, or patches of adhesive disposednear the distal end of each flap 60 (i.e., the end of the flaps 60farthest away from the longitudinal centerline l of the incontinent pad20). If the adhesive is provided in the form of strips, the strips ofadhesive are preferably between about 10 to about 20 cm in length, andbetween about 5 to about 35 millimeters in width. If the adhesive isapplied to the backsheet 36 in a generally centered rectangular patch(not shown), it should cover about 30 to about 70 percent of the area ofthe garment side 36b of the backsheet 36. Suitable adhesive may be thatspecified as 0.6 mil pass available from Century Adhesive as productnumber A305-4, or from Anchor Continental, Inc., 3 Sigma Division, ofCovington, Ohio.

4. Alternative Embodiments of the Present Invention

There are many possible alternative embodiments of the absorbent article20 of the present invention and of the multiple layer absorbent core 42incorporated therein. These include, but are not limited to theembodiments described below.

In one alternative embodiment that can be discussed with reference toFIGS. 1-3, the topsheet 34 may be eliminated, and the uppermostacquisition/distribution layer 46' can serve the function the topsheet34 generally serves. Another way of describing such an embodiment wouldbe to say that the topsheet 34 and the uppermostacquisition/distribution layer 46' are one and the same. Theacquisition/distribution layer material described herein is suitable foruse as a topsheet because it drains rapidly, and thus provides a drysurface for contact with the wearer's skin.

In one version of this first alternative embodiment, the firstacquisition/distribution layer 46' may be arranged in the form of one ormore layers or strata, each of which is provided with its own particularcharacteristics. For instance, the uppermost layer of the firstacquisition/distribution layer 46' could be comprised of a web ofmaterial (such as a nonwoven web of 3 denier fibers) that is soft andcomfortable against the wearer's skin, and the remainder of the firstacquisition/distribution layer 46' could be comprised of a nonwoven webof 15 denier fibers.

In this first alternative embodiment, the multiple layer absorbent core42 of the present invention may be referred to as a multiple layerabsorbent "body", rather than as a core since it will be positionedadjacent to and secured to the backsheet 36, and will no longer bepositioned between two elements such as the topsheet 34 and thebacksheet 36.

FIG. 6 shows another possible alternative embodiment of the multiplelayer absorbent core 42 of the present invention. In the embodimentshown in FIG. 6, the mechanism used to transport exudates from the upperacquisition/distribution layer 46' of the core 42 to the loweracquisition/distribution layer 46" comprises portions of theacquisition/distribution layer material that interconnect (or join) thefirst acquisition/distribution layer 46' and the secondacquisition/distribution layer 46". The acquisition/distribution layermaterial that joins the first acquisition/distribution layer 46' to thesecond acquisition/distribution layer 46" can be pieces of material thatare separate from the first and second acquisition/distribution layers46' and 46". Alternatively, the material that joins the twoacquisition/distribution layers could be part of one of theacquisition/distribution layers, or as shown in FIG. 6, part of both ofthe acquisition/distribution layers (in one version of the embodimentshown in FIG. 6, both acquisition/distribution layers are the same webof material). The portions of the acquisition/distribution material thatjoin the first and second acquisition/distribution layers can join suchlayers along the entire perimeters of these layers, or any portionthereof, such as only along the longitudinal edges. The different waysof interconnecting the acquisition/distribution layers described hereincan be used in addition to, or as an alternative to the apertures 52shown in the embodiment of FIGS. 1-3.

FIG. 7 shows an alternative arrangement for allowing exudates to travelfrom the first acquisition/distribution layer 46' to the secondacquisition/distribution layer 46". In the embodiment shown in FIG. 7,one or more of the acquisition/distribution layers 46 is simply madewider (or longer, or both) than the intermediate storage layer 48 so theacquisition/distribution layers 46 touch. In this alternativearrangement, it is not necessary that the acquisition/distributionlayers 46 be joined to each other, as long as they are in contact.

FIG. 8 shows an alternative embodiment in which the multiple layerabsorbent core 42 of the present invention is placed in a brief-typeincontinent pad (or "brief") 20'. The brief-type incontinent pad 20' hasthe same general components described above (longitudinal and transversecenterlines l and t; first end region 28, central region 30, and secondend region 32; topsheet 34, backsheet 36, and core 42', and the like).In addition, the brief 20' also has panels (or "ears") 66 in both thefirst and second end regions 28 and 32 adjacent the longitudinal edges22 of the brief 20', and elastically contractible leg cuffs 68. Thepanels 66 are those portions of the brief 20' that overlap (at leastpartially) when the brief 20' is fastened about the waist of the wearer.The brief 20' also has a fastening system for forming a side closure.The fastening system can be any fastening system known in the art suchas the tape tabs 70 shown in FIG. 8.

In this embodiment, the multiple layer absorbent core 42 of the presentinvention is a subcomponent of the absorbent core 42' of the brief 20'.The multiple layer absorbent core 42 of the present invention may bereferred to as the "multiple layer absorbent body" in such a case todesignate the fact that it is but one part of the absorbent core 42'. Asshown in FIG. 8, the multiple layer absorbent body 42 is smaller inlength and width than several other components of the absorbent core 42'of the brief 20'. The term "subcomponent", as used herein, means thatthe multiple layer absorbent body 42 is merely one component of theabsorbent core 42', and that there are other absorbent componentsbetween the topsheet 34 and the backsheet 36. The multiple layerabsorbent body 42 is generally rectangular in shape, and is positionedalmost entirely in the central (or crotch) portion of the brief 20'.

The cross-section of the brief 20' is shown in FIG. 9. The multiplelayer absorbent body 42 of the present invention is shown schematicallyin FIG. 9 for simplicity of illustration. It should be understood thatthe multiple layer absorbent body 42 in this embodiment can be any ofthe variations of the multiple layer absorbent core 42 disclosed in thisdescription. As shown in cross-section, the multiple layer absorbentbody 42 is wrapped in a low density (or "high loft") wrapping ofmaterial that is capable of transporting fluids ("fluid transportingwrapping" or "wrapping") 72. In one preferred embodiment, this high loftwrapping of material 72 has a caliper of about 65 mils (about 1.6 mm.)when measured in a flat, unwrapped condition under a pressure of about0.1 psi (about 1 g/cm²). The wrapped multiple layer absorbent body ispositioned on top of (in other words, it overlies) a layer of storagelayer material, such as a layer of airfelt 74. In the preferredembodiment, this layer of airfelt 74 has a basis weight from betweenabout 0.1 to about 0.5 grams per square inch (about 160 to about 780grams per square meter), most preferably about 0.2 grams/square inch(about 310 grams per square meter). The additional components of thisembodiment (the wrapping of material 72 and the layer of airfelt 74) maybe either secured to each other and/or secured to other components ofthe brief 20', such as the multiple layer absorbent body 42 and thetopsheet 34 and backsheet 36, or they may be unsecured.

In this preferred embodiment, the layer of airfelt 74 serves as anadditional storage layer. This layer of airfelt 74 is useful inincontinent brief-type products intended for use by severely incontinentpersons, and is particularly suited for handling multiple loadings ofexudates. The high loft wrapping of material 72 serves as an additionalacquisition/distribution layer to transport exudates to the layer ofairfelt 74. Thus, it could be comprised of any of the materialsspecified herein as being suitable for use in theacquisition/distribution layers 46. In other variations of theembodiment shown in FIG. 9, the wrapping could be eliminated, and liquidexudates could be transported to the layer of airfelt by aperturesprovided in the lowermost storage layer 48 of the multiple layerabsorbent body 42, or by any of the other mechanisms described above asproviding suitable passageways for the flow of exudates. In still otheralternative arrangements, the layer of airfelt 74 may include any of thetypes of absorbent gelling materials disclosed herein, includingordinary speed absorbent gelling materials and/or high-speed absorbentgelling materials. (It should also be understood that the wrapping andthe additional layer of storage layer material, could also be used inany other embodiments described herein.)

The brief 20' is provided with longitudinal barrier shields 58' alongeach longitudinal edge 22. The longitudinal barrier shields 58' needonly extend along at least a portion of at least one longitudinal edge22 of the brief 20'. In one preferred embodiment shown in FIG. 8,however, the longitudinal barrier shields 58' are essentiallyrectangular strips of material that run the length of the brief 20' andlie flat on top of the topsheet 34. As shown in FIG. 9, the topsheet 34does not wrap around and cover the longitudinal sides of the absorbentcore as it did in the incontinent pad shown in FIGS. 1-3. In the brief20', this function is served by the longitudinal barrier shields 58'. Inthe preferred embodiment of the brief 20', the longitudinal barriershields 58' are about 2.75 inches wide (about 7 cm.), and of this widthof material, about 0.75 inches (about 2 cm.) lies directly above theabsorbent core 42'. The remainder is wrapped around the sides of theabsorbent core 42' and secured to the backsheet 36. The inside edges ofthe longitudinal barrier shields 58' (that is, the longitudinal edges ofthe barrier shields 58' located closest to the longitudinal centerline)are preferably spaced about 2.5 inches (about 6.4 cm.) apart.

The longitudinal barrier shields 58' may be made of any of the materialsspecified above as being suitable for the barrier shields of theincontinent pad 20 shown in FIGS. 1-3. Preferably, the longitudinalbarrier shields 58' comprise a two layer laminate comprising a layer ofnonwoven material and a polyethylene film. The longitudinal barriershields 58' are oriented so the nonwoven material side faces upward inorder than the brief 20' will be more comfortable to wear.

In still other alternative embodiments, the multiple layer absorbentcore 42 of the present invention could, for example, instead of beingincorporated into the incontinent pads 20 shown in the drawings, beincorporated into other types of absorbent articles, such as thedisposable diapers described in U.S. Pat. No. Re. 26,151 entitled"Disposable Diaper" which reissued to Robert C. Duncan and Norma L.Baker on Jan. 31, 1967; in U.S. Pat. No. 3,860,003 entitled"Contractable Side Portions For Disposable Diaper" which issued toKenneth B. Buell on Jan. 14, 1975; and in U.S. Pat. No. 4,834,735entitled "High Density Absorbent Members Having Lower Density And LowerBasis Weight Acquisition Zones" which issued to Miguel Alemany andCharles J. Berg on May 30, 1989, the disclosures of which areincorporated herein. Such different types of absorbent articles will, ofcourse, have their own optional components which are discussed morefully in the above references, the disclosures of which are incorporatedfully herein.

5. Test Methods

Horizontal Fluid Acquisition/Distribution Rate Test

The rate at which the material used in the acquisition/distributionlayers 46 can acquire and distribute fluids is measured by a test whichhas been developed for this particular purpose. This test is known asthe "Horizontal Fluid Acquisition/Distribution Rate Test" because rateof flow through the sample is measured while the sample is in ahorizontal position during the test. The test described herein may bereferred to by any abbreviated version of its name, such as the "FluidAcquisition/Distribution Rate Test".

In the Fluid Acquisition/Distribution Rate Test, fluids are applied to asample at a predetermined rate. The rate at which fluids are applied mayexceed the rate at which the sample can acquire and distribute thesefluids, and fluids may back up and pool on top of the sample. The rateat which fluids that cannot be acquired and distributed by the sample(the overflow rate) is measured. The difference between the rate atwhich fluids are applied to the sample and the overflow rate determinesthe rate at which the sample can acquire and distribute fluids.

The Fluid Acquisition/Distribution Rate Test utilizes a device 76 whichis depicted schematically in FIG. 10. FIG. 10 is a side view of theFluid Acquisition Rate Test device 76. As shown in FIG. 10, the FluidAcquisition Rate Test device 76 has as its basic components, a sampleplatform 78; a fluid holding column 80; a column base 82 provided withremovable weights 84; a fluid overflow tube 86; a fluid overflow catchbasin 88; a balance 90; a fluid catch basin 92; an adjustable flow ratepump ("pump") 94; a fluid reservoir 96; a fluid delivery tube 98, and aplug 108.

The sample platform 78 is a Plexiglas cube measuring 4 inches×4 inches×4inches (10.2 cm.×10.2 cm.×10.2 cm.) which has a top surface designated78a. The sample platform 78 provides a surface against which pressurecan be exerted on the sample 100.

The fluid holding column 80 is constructed of Plexiglas tubing. It has acircular cross-section with an inside diameter of 1.5 inches (3.8 cm.)and an outside diameter of 1.75 inches (4.44 cm.). The length of thefluid holding column 80 should be in the range of between 7 inches and 9inches (between 17.8 cm. and 22.9 cm.). One end of the fluid holdingcolumn 80 is permanently affixed to the center of the top surface 82a ofthe base 82 so that the fluid holding column 80 is perpendicular to thebase 82.

The fluid holding column base, base 82, is constructed of a square pieceof Plexiglas 4 inches×4 inches (10.2 cm.×10.2 cm.) and 0.5 inch (1.3cm.) thick. The base 82 has a top surface 82a and a bottom surface 82b.A two inch (5.08 cm.) circular first hole 102 is drilled partiallythrough the thickness of the base 82 from the bottom surface 82b of thebase 82. The center of the first hole 102 is located in the center ofthe bottom surface 82b of the base 82. The first hole 102 penetrates thebottom surface 82b of the base 82 a depth of 0.0625 inches (0.159 cm.).A second circular hole 104 is drilled completely through the thicknessof the base 82 in center of the base 82. The second hole 104 has adiameter of 0.5 inches (1.27 cm.).

The fluid overflow tube 86 is affixed to the fluid holding column 80.The fluid overflow tube 86 is constructed of Plexiglas tubing. The fluidoverflow tube 86 has a circular cross-section with an inside diameter of0.5 inches (1.27 cm.) and an outside diameter of 0.625 inches (1.59cm.). A 0.625 inch (1.59 cm.) diameter circular hole, third hole 106, isdrilled in the fluid holding column 80 to accommodate the attachment ofthe fluid overflow tube 86. This third hole 106 is drilled perpendicularto the length of the fluid holding column 80 and is located such thatits center is 1.25 inches (3.18 cm.) above the bottom surface 82b of thebase 82. One end of the fluid overflow tube 86 is inserted into thisthird hole 106 in the fluid holding column 80 and the fluid overflowtube 86 is affixed to the fluid holding column 80. The end of the fluidoverflow tube 86 should not penetrate into the fluid holding column 80beyond the interior wall of the fluid holding column 80. The fluidoverflow tube 86 should be supported entirely by the fluid holding tube80. The fluid overflow tube 86 should be positioned so that fluids whichback up on the sample 100 and enter the fluid overflow tube 86 will flowby gravity out the unattached end of the fluid overflow tube 86 into thefluid overflow catch basin 88.

The plug 108 occupies the space inside the fluid holding column 80between the top surface 82a of the base 82 and the hole 106 that formthe opening for the fluid overflow tube 86. The plug 108 is acylindrical Plexiglas tube with an outside diameter of 1.5 inches (3.8cm.) and an inside diameter of 0.5 inches (1.3 cm.). The plug 108 has alength of 0.5 inches (1.3 cm.). The plug 108 is inserted into the fluidholding column 80 so that is rests on the top surface 82a of the base82.

The fluid overflow catch basin 88 can be any suitable vessel that iscapable of catching and holding the fluid, represented by the arrow "O",that flows out of the unattached end of the fluid overflow tube 86.

The balance 90 can be any suitable balance that is capable of measuringthe weight of the overflow catch basin 88 plus any fluid it may contain.

The fluid catch basin 92 can be any vessel capable of catching andholding any fluids which run out of the sample 100. The fluid catchbasin 92 must be of such size that the fluids collected therein do notreach the height of the bottom of the sample 100.

The pump 94 can be any variable speed pump that is capable of deliveringfluid through the delivery tube 98 at a rate of 15 cubic centimeters±0.15 second. The fluid reservoir 96 can be any suitable vessel that iscapable of holding all the fluid needed for the test.

The fluid delivery tube 98 can be any conduit that is compatible withthe pump 94 and the fluid reservoir 96. The fluid delivery tube 98 ispositioned so that fluids are discharged into the open top of the fluidholding column 80.

The test is performed by first cutting a 4 inch by 4 inch square (10.2cm. by 10.2 cm.) sample 100 of the material to be tested. The sample 100is placed on the top surface 78a of the sample platform 78. The topsurface 78a of the sample platform 78 must be horizontal. The edges ofthe sample 100 are aligned even with the edges of the sample platform78. The fluid holding column base 82 is placed on top of the sample 100so that the bottom surface 82b of the base 82 is in contact with thesample 100. The edges of the base 82 are aligned even with the edges ofthe sample 100. The weights 84 are equally distributed near theperimeter of the base 82 so they exert equal pressure on all portions ofthe sample 100. The amount of weight used should be such that the totalweight of the weights 84, the fluid holding column base 82, the fluidholding column 80, and the fluid overflow tube 86 equals 2900 grams.

The pump 94 is set to deliver a fluid at a rate of 15 cubiccentimeters/second for a period of ten seconds. The fluid used is asynthetic urine known as Jayco SynUrine which is available from JaycoPharmaceuticals Company of Camp Hill, Pa. The formula for the syntheticurine is: 2.0 g/l of KCl; 2.0 g/l of Na₂ SO₄ ; 0.85 g/l of (NH₄)H₂ PO₄ ;0.15 g/l (NH₄)₂ HPO₄ ; 0.19 g/l of CaCl₂ and 0.23 g/l of MgCl₂. All ofthe chemicals are of reagent grade. The pH of the synthetic urine is inthe range of 6.0 to 6.4.

The pump 94 is started and synthetic urine is delivered to the sample atthe rate of 15 cubic centimeters/second for a period of 10 seconds ±0.1seconds. The synthetic urine is pumped from the fluid reservoir 96 bythe pump 94 through the fluid delivery tube 98 into the fluid holdingcolumn 80. The synthetic urine is applied to the sample 100 through thehole in the base 82 of the fluid holding column 80. The synthetic urinetypically flows through the sample 100 in the direction of the arrows,and then flows out of the sample 100 where it is collected in the fluidcatch basin 92.

If the rate at which the fluid can flow into and through the sample 100is less than the rate at which fluid is being pumped, fluid backs up inthe fluid holding column 80. When the level of fluid held in the fluidholding column 80 reaches the level of the fluid overflow tube 86, thefluid begins to flow through the fluid overflow tube 86 and is collectedin the fluid overflow catch basin 88. The weight of fluid present in thefluid overflow catch basin 88 is measured by the balance 90.

The pump 94 is stopped after 10 seconds ±0.1 seconds. The weight offluid in the overflow catch basin 88 is then recorded.

The Fluid Acquisition/Distribution Rate described herein is the averageflow rate of synthetic urine in cubic centimeters through the sampleover the ten second test period. It is calculated as follows: ##EQU1##

Where W=weight of fluid in the fluid overflow collection basin after 10seconds (in cubic centimeters)

Absorption Rate/Capacity Test ("Tea Bag" Test)

The rate at which the absorbent gelling material absorbs fluids and theabsorptive capacity of the absorbent gelling materials used in thestorage layers 48 is measured by a test that will be referred to as the"Absorption Rate/Capacity Test" or the "Tea Bag" Test. The Tea Bag Testis a type of test that is fairly standard in the industry among thosewho use absorbent gelling materials. It is important, however, that thespecific version of the Tea Bag Test described herein be followed.

The test essentially involves placing the absorbent gelling material tobe tested within a "tea bag" and dipping the tea bag into a syntheticurine solution for a specified period of time. For the purposes of thistest, the Absorptive Capacity of the absorbent gelling material is theamount of synthetic urine the absorbent gelling material absorbs over aten minute time period. The Absorptive Capacity is generally expressedin units of grams of fluid absorbed per gram of absorbent gellingmaterial. The percent of absorptive capacity the absorbent gellingmaterial is capable of absorbing in ten seconds is equal to the ratio ofthe absorptive capacity after ten seconds to the Absorptive Capacity(after ten minutes) multiplied by 100.

Apparatus

The following equipment is needed for the Tea Bag Test:

    ______________________________________                                        Balance Top loading, 1 mg sensitivity, Mettler PC-220,                                Fisher #01-913-382, or equivalent                                     Beaker  2,000 ml., Kimax brand, Fisher #02-539R, (and other                           sizes as needed), or equivalent                                       Heat Sealer                                                                           T-Bar plastic Model T-7, 115V, 65W, Harwil Co.,                               Santa Monica, California, or equivalent                               Paper   Tea bag, Dexter 1234-heat sealable, or lower                                  porosity, if required, Dexter Corp., Windsor Locks,                           CT 06096, or equivalent                                               Timer   A timer able to time 10 minutes ± 0.1 seconds,                             Fisher #14-653, or equivalent                                         Paper   Weighing, Fisher #09-898-12A, or equivalent                           Scissors                                                                              Standard type                                                         Tongs   Crucible, Fisher #15-200, or equivalent                               Ruler   Stainless steel metric, from L. S. Starrett, Athol,                           Mass. 01331, or equivalent                                            ______________________________________                                    

Solutions

The following solution is needed:

    ______________________________________                                        Synthetic                                                                            Jayco SynUrine from Jayco Pharmaceuticals Company                      Urine  of Camp Hill, Pennsylvania, or equivalent                              ______________________________________                                    

Procedure

The following procedure is conducted under standard laboratoryconditions at 23° C. (73° F.) and 50% relative humidity.

The tea bag material is cut into 6 cm×12 cm rectangles, using scissorsor a 6 cm×12 cm cutting die. The cut tea bag material is then folded inhalf lengthwise and sealed along any two open sides with a T-bar sealerto produce 6 cm×6 cm tea bag squares.

After the tea bag has been prepared, 0.200 grams, plus or minus 0.005grams, of the absorbent gelling material is weighed on weighing paper.The absorbent gelling material is then transferred into a tea bag. Thetop (or open end) of the tea bag is sealed. An empty tea bag is sealedat the top and is used as a blank.

Approximately 400 milliliters of saline solution is poured into the2,000 milliliter beaker. The blank tea bag is submerged in the salinesolution. The tea bag containing the absorbent gelling material (thesample tea bag) is held horizontally to distribute the material evenlythroughout the tea bag. The tea bag is laid on the surface of the salinesolution. The tea bag is submerged in the synthetic urine and soaked for10 seconds ±0.1 seconds.

After soaking both tea bags in the saline solution for a period of 10seconds ±0.1 seconds, the tea bags are removed. The tea bags are removedusing the tongs to grip the edges of the tea bags. The edges of the teabags are gripped so that the folded edge of each bag is down. The teabags are suspended with the folded edge down. The tea bags should nottouch each other or the work area. One method for hanging the tea bagsis to set up a rod with clamps between two stands. Binder clips may beattached to the rod and the tea bags may be suspended from the binderclips.

After a drying period of 10 minutes ±10 seconds, both the sample and theblank tea bags are weighed. The weight of the sample tea bag is recordedas W₁, and the weight of the blank tea bag is recorded as W₂.

The above procedure is repeated with another sample and blank tea bagand the soak time is changed to 10 minutes ±10 seconds to approximatethe total absorptive capacity of the absorbent gelling material. Theweight of the sample tea bag is recorded as W₁₀, and the weight of theblank tea bag is recorded as W₂₀.

The percentage of absorptive capacity for a period of ten seconds forthe sample is calculated as follows: ##EQU2##

(Where 0.20 grams is the dry weight of the sample) ##EQU3##

The average rate of fluid absorbency in grams of synthetic urine persecond per gram of absorbent gelling material can also be calculatedusing the Tea Bag Test. The following calculation is used: ##EQU4##

(Where 10 seconds is the length of time the sample was submerged in thesynthetic urine.)

In use, it is believed that the exudate acquisition/distribution layeris capable of quickly absorbing exudates as they are deposited on theabsorbent article and distributing such exudates to the lower storagelayer in a manner that substantially reduces or eliminates priorproblems of saturation of the materials adjacent the zone of exudateapplication and gel blocking. It is believed that the combination of thelayers of the particular materials used provides a structure that isalso capable of quickly storing the absorbed liquids.

While not wishing to be bound by any particular theory, it is believedthat the multiple layer absorbent core distributes exudates by acascading effect. It is believed that the manner of acquisition,distribution, and storage of the multiple layer absorbent core can beanalogized to the filling of an ice cube tray with water in that whenone region of the absorbent core is filled, exudates will quickly flowlaterally to the sides of the filled region to begin filling otherunfilled regions.

The present invention, in theory, operates by a using a layer that hasgood fluid transporting properties in the X-Y plane as the top layer(referred to herein as "horizontal" fluid acquisition/distribution), andprovides a storage layer underneath the top layer. The storage layerneed not be particularly good at transporting fluids in the X-Y plane.In fact, if the storage layer is comprised of high-speed fibrousabsorbent gelling materials, such as FIBERSORB, the storage layer may berelatively poor at transporting fluids in the X-Y plane, but very goodat transporting fluids in the Z-direction. In such an embodiment, theacquisition/distribution layer is believed to function by spreading thefluids out on top of the storage layer, and the storage layer quicklytakes these in in the Z-direction.

(The term "Z-direction", as used herein, is an orientation with respectto the absorbent article 20 of the present invention if the absorbentarticle 20 is placed in a Cartesian coordinate system in its flat, laidout condition of FIG. 1 so that the garment surface 20b of the absorbentarticle 20 lies in the plane formed by the x and y axes (i.e.,horizontal). The longitudinal and transverse centerlines l and t of theabsorbent article lie in the plane formed by the x and y axes. The"Z-direction" is the direction that is perpendicular to the plane ofeither surface of the absorbent article 20 when it is in such a flat,laid out configuration.)

The disposable absorbent article of the present invention is believed tohave improved containment performance because it has an absorbent corethat is capable of immediately taking in and storing exudates that aredeposited on it. This improvement in containment performance allows thedisposable absorbent article to be made smaller than prior disposableabsorbent articles, particularly brief-type incontinent products. As aresult, the absorbent articles of the present invention can fit closerto the wearer's body. The absorbent articles of the present inventioncan fit in the wearer's usual undergarments. The reduction in size ofthe absorbent article also makes it more comfortable to wear, and morediscreet for the wearer.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. An absorbent article comprising:a liquid pervious topsheet; a liquid in, pervious backsheet joined to said topsheet; a multiple layer absorbent core positioned between said topsheet and said backsheet, said multiple layer absorbent core comprising at least one pair of layers, wherein each pair of layers comprises at least one acquisition/distribution layer and at least one storage layer, each pair of layers being arranged so that at least one storage layer is positioned subjacent each acquisition/distribution layer, whereineach acquisition/distribution layer comprises a material having an acquisition/distribution rate of at least about 2 cubic centimeters of synthetic urine per second when said acquisition/distribution layer is placed under a pressure of about 28 grams per square centimeter; each storage layer at least partially comprises an absorbent gelling material which has a total absorptive capacity of at least about 25 times its dry weight and is capable of absorbing at least about 0.8 grams of synthetic urine per second per gram of absorbent gelling material; and each pair of layers is in liquid communication with each adjacent pair of layers.
 2. An absorbent article having a first end region, a second end region, a central region disposed between said first end region and said second end region, two spaced apart longitudinal edges, two spaced apart end edges, at least portions of said longitudinal and end edges being arcuate, wherein the width of the widest portion of said first end region is greater than the width of said central region and said second end region, and said longitudinal edges are outwardly arcuate with relation to each other in said first end region, inwardly arcuate in at least a portion of said central region, generally parallel to each other in said second end region, and said end edges are convex outwardly, said absorbent article comprising:a liquid pervious topsheet; a liquid impervious backsheet joined to said topsheet; a multiple layer absorbent core positioned between said topsheet and said backsheet, said multiple layer absorbent core comprisingat least one acquisition/distribution layer having an acquisition/distribution rate of at least about 2 cubic centimeters of synthetic urine per second when said acquisition/distribution layer is placed under a pressure of about 28 grams per square centimeter; and a storage layer positioned subjacent each acquisition/distribution layer, said storage layer at least partially comprising an absorbent gelling material which is capable of absorbing synthetic urine at such a rate that said absorbent gelling material reaches at least about 40% of its absorptive capacity in less than or equal to about 10 seconds.
 3. A multiple layer absorbent core suitable for use in an absorbent article, said absorbent core comprising:at least one acquisition/distribution layer having an acquisition/distribution rate of at least about 2 cubic centimeters of synthetic urine per second when said acquisition/distribution layer is placed under a pressure of about 28 grams per square centimeter; and a storage layer positioned subjacent each acquisition/distribution layer, said storage layer at least partially comprising an absorbent gelling material which is capable of absorbing synthetic urine at such a rate that said absorbent gelling material reaches at least about 40% of its absorptive capacity in less than or equal to about 10 seconds.
 4. An absorbent article comprising:a multiple layer absorbent body which comprises at least one pair of layers, wherein each pair of layers comprises at least one acquisition/distribution layer and at least one storage layer positioned subjacent said acquisition/distribution layer, andeach acquisition/distribution layer having an acquisition/distribution rate of at least about 2 cubic centimeters of synthetic urine per second when said acquisition/distribution layer is placed under a pressure of about 28 grams per square centimeter; and each storage layer at least partially comprises an absorbent gelling material which is capable of absorbing synthetic urine at such a rate that said absorbent gelling material reaches at least about 40% of its absorptive capacity in less than or equal to about 10 seconds; wherein each pair of layers is in liquid communication with each adjacent pair of layers, and a liquid impervious backsheet joined to said absorbent body.
 5. An absorbent article comprising:a multiple layer absorbent body which comprises at least one pair of layers, wherein each pair of layers comprises at least one acquisition/distribution layer and at least one storage layer positioned subjacent said acquisition/distribution layer, andeach acquisition/distribution layer having an acquisition/distribution rate of at least about 2 cubic centimeters of synthetic urine per second when said acquisition/distribution layer is placed under a pressure of about 28 grams per square centimeter; and each storage layer at least partially comprises an absorbent gelling material having a total absorptive capacity of at least about 25 times its dry weight and being capable of absorbing fluids at a rate of at least about 0.8 grams of synthetic urine per gram of absorbent gelling material; wherein each pair of layers is in liquid communication with each adjacent pair of layers, and a liquid impervious backsheet joined to said absorbent body.
 6. An absorbent article comprising:a liquid pervious topsheet; a liquid impervious backsheet joined to said topsheet; a multiple layer absorbent core positioned between said topsheet and said backsheet, said multiple layer absorbent core comprising at least one pair of layers, wherein each pair of layers comprises at least one acquisition/distribution layer and at least one storage layer, each pair of layers being arranged so that at least one storage layer is positioned subjacent each acquisition/distribution layer, whereineach acquisition/distribution layer comprises a nonwoven material having a basis weight of between about 17 to about 270 grams/square meter and a density of between about 0.02 to about 0.1 grams/cubic centimeter; each storage layer at least partially comprises an absorbent gelling material which is capable of absorbing synthetic urine at such a rate that said absorbent gelling material reaches at least about 40% of its absorptive capacity in less than or equal to about 10 seconds; and each pair of layers is in liquid communication with each adjacent pair of layers.
 7. The absorbent article of claim 6 wherein said multiple layer absorbent core comprises four layers which are arranged in the following order beneath the topsheet: a first acquisition/distribution layer; a first storage layer; a second acquisition/distribution layer; and a second storage layer.
 8. The absorbent article of claim 7 wherein said absorbent gelling material is in fibrous form.
 9. An absorbent article comprising:a liquid pervious topsheet; a liquid impervious backsheet joined to said topsheet; a multiple layer absorbent core positioned between said topsheet and said backsheet, said multiple layer absorbent core comprising at least one pair of layers, wherein each pair of layers comprises at least one acquisition/distribution layer and at least one storage layer, each pair of layers being arranged so that at least one storage layer is positioned subjacent each acquisition/distribution layer, whereineach acquisition/distribution layer comprises a nonwoven material having a basis weight of between about 17 to about 270 grams/square meter and a density of between about 0.02 to about 0.1 grams/cubic centimeter; each storage layer at least partially comprises an absorbent gelling material which has a total absorptive capacity of at least about 25 times its dry weight and is capable of absorbing at least about 0.8 grams of synthetic urine per second per gram of absorbent gelling material; and each pair of layers is in liquid communication with each adjacent pair of layers.
 10. The absorbent article of claim 9 wherein said multiple layer absorbent core comprises four layers which are arranged in the following order beneath the topsheet: a first acquisition/distribution layer; a first storage layer; a second acquisition/distribution layer; and a second storage layer.
 11. The absorbent article of claim 10 wherein said absorbent gelling material is in fibrous form.
 12. An absorbent article having a first end region, a second end region, a central region disposed between said first end region and said second end region, said first end region and said second end region having panels that at least partially overlap when the absorbent article is worn about the waist of the wearer, two spaced apart longitudinal edges, two spaced apart end edges, said absorbent article comprising:a liquid pervious topsheet; a liquid impervious backsheet joined to said topsheet; an absorbent core positioned between said topsheet and said backsheet, said absorbent core comprising a multiple layer absorbent body comprising at least one pair of layers, wherein each pair of layers comprises at least one acquisition/distribution layer and at least one storage layer, each pair of layers being arranged so that at least one storage layer is positioned subjacent each acquisition/distribution layer, whereineach acquisition/distribution layer comprises a material having an acquisition/distribution rate of at least about 2 cubic centimeters of synthetic urine per second when said acquisition/distribution layer is placed under a pressure of about 28 grams per square centimeter; each storage layer at least partially comprises an absorbent gelling material which is capable of absorbing synthetic urine at such a rate that said absorbent gelling material reaches at least about 40% of its absorptive capacity in less than or equal to about 10 seconds; and each pair of layers is in liquid communication with each adjacent pair of layers.
 13. The absorbent article of claim 12 further comprising a longitudinal barrier shield extending along at least a portion of at least one longitudinal edge of said absorbent article.
 14. The absorbent article of claim 13 wherein said longitudinal barrier shield comprises a two layer laminate comprising a layer of nonwoven material and a polyethylene film.
 15. The absorbent article of claim 13 wherein said absorbent article has a body surface and a garment surface, and said longitudinal barrier shield comprises a substance printed on said body surface of said absorbent article.
 16. An absorbent article comprising:a liquid pervious topsheet; a liquid impervious backsheet joined to said topsheet; a multiple layer absorbent core positioned between said topsheet and said backsheet, said multiple layer absorbent core comprising at least one pair of layers, wherein each pair of layers comprises at least one acquisition/distribution layer and at least one storage layer, each pair of layers being arranged so that at least one storage layer is positioned subjacent each acquisition/distribution layer, whereineach acquisition/distribution layer having an acquisition/distribution rate of at least about 2 cubic centimeters of synthetic urine per second when said acquisition/distribution layer is placed under a pressure of about 28 grams per square centimeter; each storage layer at least partially comprises an absorbent gelling material which is capable of absorbing synthetic urine at such a rate that said absorbent gelling material reaches at least about 40% of its absorptive capacity in less than or equal to about 10 seconds; and each pair of layers is in liquid communication with each adjacent pair of layers.
 17. The absorbent article of claim 16 wherein each acquisition/distribution layer comprises a foam.
 18. The absorbent article of claim 16 wherein each acquisition/distribution layer is dry resilient and wet resilient.
 19. The absorbent article of claim 16 wherein each storage layer is comprised of between about 10% to about 100% absorbent gelling materials.
 20. The absorbent article of claim 16 wherein each storage layer is comprised of between about 0% to about 80% natural fibers.
 21. The absorbent article of claim 16 wherein each storage layer is comprised of between about 0% to about 80% cross-linked cellulose fibers.
 22. The absorbent article of claim 16 wherein each storage layer is comprised of between about 0% to about 80% synthetic fibers.
 23. The absorbent article of claim 16 wherein each storage layer is comprised of between about 0% to about 20% binder fiber.
 24. The absorbent article of claim 16 wherein said absorbent gelling material is in particulate form.
 25. The absorbent article of claim 16 wherein said absorbent gelling material is in fibrous form.
 26. An adult incontinent article according to claim
 16. 27. A disposable diaper according to claim
 16. 28. A sanitary napkin according to claim
 16. 29. The absorbent article of claim 16 wherein each acquisition/distribution layer comprises a nonwoven material.
 30. The absorbent article of claim 29 wherein each acquisition/distribution layer comprises a nonwoven web of fibers bonded into an open structure.
 31. The absorbent article of claim 29 wherein each acquisition/distribution layer comprises a nonwoven web of unbonded fibers arranged in an open structure.
 32. The absorbent article of claim 29 wherein each acquisition/distribution layer comprises at least about 10% by weight synthetic fibers.
 33. The absorbent article of claim 29 wherein each acquisition/distribution layer is at least partially comprised of cross-linked cellulose fibers.
 34. The absorbent article of claim 16 wherein said adjacent pairs of layers are maintained in liquid communication by at least one passageway between adjacent pairs of layers.
 35. The absorbent article of claim 34 wherein at least one passageway comprises at least one aperture in at least a portion of the surface area of at least one storage layer.
 36. The absorbent article of claim 34 further comprising a longitudinal centerline, wherein at least one storage layer is arranged in the form of at least two strips, at least one of said strips being located on each side of the longitudinal centerline of said absorbent article, wherein said strips on opposite sides of said longitudinal centerline form a space therebetween, and said space between said strips serves as said passageway.
 37. The absorbent article of claim 34 wherein at least one acquisition/distribution layer comprises the same piece of material as the acquisition/distribution layer in an adjacent pair of layers.
 38. The absorbent article of claim 34 wherein said passageway comprises at least a portion of a first acquisition/distribution layer which contacts a second acquisition/distribution layer.
 39. The absorbent article of claim 38 further comprising two spaced apart longitudinal edges and two spaced apart end edges wherein said portion of said first acquisition/distribution layer which contacts said second acquisition/distribution layer lies at least along the longitudinal edges of the absorbent article.
 40. The absorbent article of claim 16 wherein said absorbent article has two spaced apart longitudinal edges and two spaced apart end edges, and said absorbent article further comprises a longitudinal barrier shield extending along at least a portion of at least one of the longitudinal edges of said absorbent article.
 41. The absorbent article of claim 40 wherein said absorbent article further comprises a transverse barrier shield extending along at least a portion of at least one of the end edges of said absorbent article.
 42. The absorbent article of claims 40 or 41 wherein each barrier shield comprises a two layer laminate comprising a layer of nonwoven material and a polyethylene film.
 43. The absorbent article of claims 40 or 41 wherein said absorbent article has a body surface and a garment surface, and each barrier shield comprises a substance printed on said body surface of said absorbent article. 